diff --git a/include/DOM/Attr.hpp b/include/DOM/Attr.hpp
index 6efa777b..6f5ec974 100644
--- a/include/DOM/Attr.hpp
+++ b/include/DOM/Attr.hpp
@@ -31,6 +31,8 @@ class Attr : public Node<stringT, string_adaptorT>
     Attr(const Attr& rhs) : NodeT(rhs) { }
     explicit Attr(const NodeT& rhs) : NodeT(rhs)  
     {
+	  if(NodeT::impl_ == 0) // null nodes can always be cast
+		return;
       if(rhs.getNodeType() != NodeT::ATTRIBUTE_NODE)
         throw std::bad_cast();
     } // Attr
diff --git a/include/DOM/CDATASection.hpp b/include/DOM/CDATASection.hpp
index 9aa48f2d..ffb65b0d 100644
--- a/include/DOM/CDATASection.hpp
+++ b/include/DOM/CDATASection.hpp
@@ -25,6 +25,8 @@ class CDATASection : public Text<stringT, string_adaptorT>
     CDATASection(const CDATASection& rhs) : Text<stringT, string_adaptorT>(rhs) { }
     explicit CDATASection(const Node<stringT, string_adaptorT>& rhs) : Text<stringT, string_adaptorT>(rhs, 0)  
     {
+	  if(NodeT::impl_ == 0) // null nodes can always be cast
+		return;
       if(rhs.getNodeType() != Node_base::CDATA_SECTION_NODE)
         //throw std::runtime_error("bad_cast: Cannot convert Node to CDATA section");
         throw std::bad_cast();
diff --git a/include/DOM/CharacterData.hpp b/include/DOM/CharacterData.hpp
index 2b54dd98..f0d62a89 100644
--- a/include/DOM/CharacterData.hpp
+++ b/include/DOM/CharacterData.hpp
@@ -27,6 +27,8 @@ class CharacterData : public Node<stringT, string_adaptorT>
     CharacterData(const CharacterData& rhs) : NodeT(rhs) { }
     explicit CharacterData(const NodeT& rhs) : NodeT(rhs)  
     {
+	  if(NodeT::impl_ == 0) // null nodes can always be cast
+		return;
       typename NodeT::Type type = rhs.getNodeType();
       if((type != NodeT::TEXT_NODE) && (type != NodeT::CDATA_SECTION_NODE))
         throw std::runtime_error("bad_cast: Cannot cast Node to Character Data");
diff --git a/include/DOM/Comment.hpp b/include/DOM/Comment.hpp
index a7ce119c..0b3d6aee 100644
--- a/include/DOM/Comment.hpp
+++ b/include/DOM/Comment.hpp
@@ -24,7 +24,9 @@ class Comment : public CharacterData<stringT, string_adaptorT>
     Comment(const Comment& rhs) : CharacterData<stringT, string_adaptorT>(rhs) { }
     explicit Comment(const Node<stringT, string_adaptorT>& rhs) : CharacterData<stringT, string_adaptorT>(rhs)  
     {
-      if(dynamic_cast<Comment_impl<stringT, string_adaptorT>*>(rhs.impl()) == 0)
+	  if(NodeT::impl_ == 0) // null nodes can always be cast
+		return;
+      if(rhs.getNodeType() != Node<stringT, string_adaptorT>::COMMENT_NODE)
         throw std::bad_cast();
     } // Comment
 }; // class Comment
diff --git a/include/DOM/Document.hpp b/include/DOM/Document.hpp
index 538a0e7a..85d84a42 100644
--- a/include/DOM/Document.hpp
+++ b/include/DOM/Document.hpp
@@ -45,6 +45,8 @@ class Document : public Node<stringT, string_adaptorT>
     Document(const Document& rhs) : Node<stringT, string_adaptorT>(rhs) { }
     explicit Document(const Node<stringT, string_adaptorT>& rhs) : Node<stringT, string_adaptorT>(rhs)  
     {
+	  if(NodeT::impl_ == 0) // null nodes can always be cast
+		return;
       if(rhs.getNodeType() != Node<stringT, string_adaptorT>::DOCUMENT_NODE)
         throw std::bad_cast();
     } // Document
diff --git a/include/DOM/DocumentFragment.hpp b/include/DOM/DocumentFragment.hpp
index 8e4edfff..d9ec5545 100644
--- a/include/DOM/DocumentFragment.hpp
+++ b/include/DOM/DocumentFragment.hpp
@@ -26,6 +26,8 @@ class DocumentFragment : public Node<stringT, string_adaptorT>
     DocumentFragment(const DocumentFragment& rhs) : Node<stringT, string_adaptorT>(rhs) { }
     explicit DocumentFragment(const Node<stringT, string_adaptorT>& rhs) : Node<stringT, string_adaptorT>(rhs)  
     {
+	  if(NodeT::impl_ == 0) // null nodes can always be cast
+		return;
       if(rhs.getNodeType() != Node<stringT, string_adaptorT>::DOCUMENT_FRAGMENT_NODE)
         throw std::bad_cast();
     }
diff --git a/include/DOM/DocumentType.hpp b/include/DOM/DocumentType.hpp
index b9aa208f..7a39ee1e 100644
--- a/include/DOM/DocumentType.hpp
+++ b/include/DOM/DocumentType.hpp
@@ -33,6 +33,8 @@ class DocumentType : public Node<stringT, string_adaptorT>
     DocumentType(const DocumentType& rhs) : NodeT(rhs) { }
     explicit DocumentType(const NodeT& rhs) : NodeT(rhs)  
     {
+	  if(NodeT::impl_ == 0) // null nodes can always be cast
+		return;
       if(rhs.getNodeType() != NodeT::DOCUMENT_TYPE_NODE)
         throw std::bad_cast();
     } // DocumentType
diff --git a/include/DOM/Element.hpp b/include/DOM/Element.hpp
index 4083ae41..91c08f0d 100644
--- a/include/DOM/Element.hpp
+++ b/include/DOM/Element.hpp
@@ -34,6 +34,8 @@ class Element : public Node<stringT, string_adaptorT>
     Element(const Element& rhs) : NodeT(rhs) { }
     explicit Element(const NodeT& rhs) : NodeT(rhs)  
     {
+	  if(NodeT::impl_ == 0) // null nodes can always be cast
+		return;
       if(rhs.getNodeType() != NodeT::ELEMENT_NODE)
         throw std::bad_cast();
     } // Element
diff --git a/include/DOM/Entity.hpp b/include/DOM/Entity.hpp
index 120f7c9c..a176ae0a 100644
--- a/include/DOM/Entity.hpp
+++ b/include/DOM/Entity.hpp
@@ -24,22 +24,24 @@ class Entity : public Node<stringT, string_adaptorT>
     typedef Entity_impl<stringT, string_adaptorT> Entity_implT;
 
     Entity() : Node<stringT, string_adaptorT>() { }
-    explicit Entity(Entity_impl<stringT, string_adaptorT>* impl) : Node<stringT>(impl) { }
+    explicit Entity(Entity_impl<stringT, string_adaptorT>* impl) : Node<stringT, string_adaptorT>(impl) { }
     Entity(const Entity& rhs) : Node<stringT, string_adaptorT>(rhs) { }
-    explicit Entity(const Node<stringT, string_adaptorT>& rhs) : Node<stringT>(rhs)  
+    explicit Entity(const Node<stringT, string_adaptorT>& rhs) : Node<stringT, string_adaptorT>(rhs)  
     {
-      if(rhs.getNodeType() != Node<stringT, string_adaptorT>::Entity_NODE)
+	    if(NodeT::impl_ == 0) // null nodes can always be cast
+        return;
+      if(rhs.getNodeType() != Node_base::ENTITY_NODE)
         throw std::bad_cast();
     }
 
-    stringT getPublicId() const { nImpl()->getPublicId(); }
+    stringT getPublicId() const { return nImpl()->getPublicId(); }
 
-    stringT getSystemId() const { nImpl()->getSystemId(); }
+    stringT getSystemId() const { return nImpl()->getSystemId(); }
 
-    stringT getNotationName() const { nImpl()->getNotationName(); }
+    stringT getNotationName() const { return nImpl()->getNotationName(); }
 
   private:
-    Entity_implT* nImpl() { return dynamic_cast<Entity_implT*>(NodeT::impl()); }
+    Entity_implT* nImpl() const { return dynamic_cast<Entity_implT*>(*NodeT::impl_); }
 }; // class Entity
 
 //////////////////////////////////////////////////////////
diff --git a/include/DOM/EntityReference.hpp b/include/DOM/EntityReference.hpp
index 7f8c5eca..3206ef46 100644
--- a/include/DOM/EntityReference.hpp
+++ b/include/DOM/EntityReference.hpp
@@ -28,7 +28,9 @@ class EntityReference : public Node<stringT, string_adaptorT>
     EntityReference(const EntityReference& rhs) : NodeT(rhs) { }
     explicit EntityReference(const NodeT& rhs) : NodeT(rhs)  
     {
-      if(dynamic_cast<EntityReference_implT*>(rhs.impl()) == 0)
+	  if(NodeT::impl_ == 0) // null nodes can always be cast
+		return;
+      if(rhs.getNodeType() != Node_base::ENTITY_REFERENCE_NODE)
         throw std::bad_cast();
     } // EntityReference
 }; // class EntityReference
diff --git a/include/DOM/NodeList.hpp b/include/DOM/NodeList.hpp
index ed93f04a..63d078ad 100644
--- a/include/DOM/NodeList.hpp
+++ b/include/DOM/NodeList.hpp
@@ -39,7 +39,12 @@ class NodeList
 
     Node<stringT, string_adaptorT> item(unsigned int index) const { return impl_->item(index); }
 
-    unsigned int getLength() const { return impl_->getLength(); }
+    unsigned int getLength() const 
+	{ 
+      if(impl_ == 0)
+		return 0;
+	  return impl_->getLength(); 
+	} // getLength
 
   private:
     Proxy<NodeList_impl<stringT, string_adaptorT> > impl_;
diff --git a/include/DOM/Notation.hpp b/include/DOM/Notation.hpp
index 06d6207b..0d4d61dd 100644
--- a/include/DOM/Notation.hpp
+++ b/include/DOM/Notation.hpp
@@ -29,16 +29,18 @@ class Notation : public Node<stringT, string_adaptorT>
     Notation(const Notation& rhs) : NodeT(rhs) { }
     explicit Notation(const NodeT& rhs) : NodeT(rhs)  
     {
+      if(NodeT::impl_ == 0) // null nodes can always be cast
+        return;
       if(rhs.getNodeType() != Node_base::NOTATION_NODE)
         throw std::bad_cast();
     }
 
-    stringT getPublicId() const { nImpl()->getPublicId(); }
+    stringT getPublicId() const { return nImpl()->getPublicId(); }
 
-    stringT getSystemId() const { nImpl()->getSystemId(); }
+    stringT getSystemId() const { return nImpl()->getSystemId(); }
 
   private:
-    Notation_implT* nImpl() { return dynamic_cast<Notation_implT*>(NodeT::impl()); }
+    Notation_implT* nImpl() const { return dynamic_cast<Notation_implT*>(*NodeT::impl_); }
 }; // class Notation
 
 //////////////////////////////////////////////////////////
diff --git a/include/DOM/ProcessingInstruction.hpp b/include/DOM/ProcessingInstruction.hpp
index e9f86989..e598d219 100644
--- a/include/DOM/ProcessingInstruction.hpp
+++ b/include/DOM/ProcessingInstruction.hpp
@@ -26,6 +26,8 @@ class ProcessingInstruction : public Node<stringT, string_adaptorT>
     ProcessingInstruction(const ProcessingInstruction& rhs) : Node<stringT, string_adaptorT>(rhs) { }
     explicit ProcessingInstruction(const Node<stringT, string_adaptorT>& rhs) : Node<stringT, string_adaptorT>(rhs)  
     {
+	  if(NodeT::impl_ == 0) // null nodes can always be cast
+		return;
       if(rhs.getNodeType() != Node<stringT, string_adaptorT>::PROCESSING_INSTRUCTION_NODE)
         throw std::bad_cast();
     }
diff --git a/include/DOM/Simple/AttrImpl.hpp b/include/DOM/Simple/AttrImpl.hpp
index 6aeb280c..e5c5dc47 100644
--- a/include/DOM/Simple/AttrImpl.hpp
+++ b/include/DOM/Simple/AttrImpl.hpp
@@ -134,6 +134,14 @@ class AttrImpl : public DOM::Attr_impl<stringT, string_adaptorT>,
 
     void setSpecified(bool specified) { specified_ = specified; }
 
+	bool isOrphaned()
+	{
+		if(!ownerElement_)
+			return true;
+
+		return NodeT::ownerDoc_->isOrphaned(this);
+	} // isOrphaned
+
   protected:
     void cloneChildren(AttrImpl* clone) const
     {
diff --git a/include/DOM/Simple/AttrMap.hpp b/include/DOM/Simple/AttrMap.hpp
index 4fab48f0..e3eea0ab 100644
--- a/include/DOM/Simple/AttrMap.hpp
+++ b/include/DOM/Simple/AttrMap.hpp
@@ -61,9 +61,15 @@ class AttrMap : public NamedNodeMapImpl<stringT, string_adaptorT>
 
     DOMAttr_implT* setAttributeNode(DOMAttr_implT* newAttr)
     {
+      return dynamic_cast<DOMAttr_implT*>(setNamedItem(newAttr));
+    } // setAttributeNode
+    virtual DOMNode_implT* setNamedItem(DOMNode_implT* newAttr)
+    {
+      throwIfReadOnly();
+	    checkNotInUse(newAttr);
       dynamic_cast<AttrImplT*>(newAttr)->setOwnerElement(ownerElement_);
       return dynamic_cast<DOMAttr_implT*>(NamedNodeMapImplT::setNamedItem(newAttr));
-    } // setAttributeNode
+    } // setNamedItem
 
     DOMAttr_implT* removeAttributeNode(DOMAttr_implT* oldAttr)    
     {
@@ -103,9 +109,15 @@ class AttrMap : public NamedNodeMapImpl<stringT, string_adaptorT>
 
     DOMAttr_implT* setAttributeNodeNS(DOMAttr_implT* newAttr)    
     {
+      return dynamic_cast<DOMAttr_implT*>(setNamedItemNS(newAttr));
+    } // setAttributeNodeNS
+    virtual DOMNode_implT* setNamedItemNS(DOMNode_implT* newAttr)
+    {
+      throwIfReadOnly();
+	    checkNotInUse(newAttr);
       dynamic_cast<AttrImplT*>(newAttr)->setOwnerElement(ownerElement_);
       return dynamic_cast<DOMAttr_implT*>(NamedNodeMapImplT::setNamedItemNS(newAttr));
-    } // setAttributeNodeNS
+    } // setNamedItem
 
     bool hasAttribute(const stringT& name) const    
     {
@@ -181,6 +193,13 @@ class AttrMap : public NamedNodeMapImpl<stringT, string_adaptorT>
       return 0;
     } // getDefaultAttrs
 
+	  void checkNotInUse(DOMNode_implT* newAttr)
+	  { 
+      AttrImplT* attr = dynamic_cast<AttrImplT*>(newAttr);
+	    if(!attr->isOrphaned())
+        throw DOM::DOMException(DOM::DOMException::INUSE_ATTRIBUTE_ERR);
+	  } // checkNotInUse
+
     ElementImplT* ownerElement_;
 }; // class AttrMap
 
diff --git a/include/DOM/Simple/DocumentImpl.hpp b/include/DOM/Simple/DocumentImpl.hpp
index 4c588378..8ef5c26d 100644
--- a/include/DOM/Simple/DocumentImpl.hpp
+++ b/include/DOM/Simple/DocumentImpl.hpp
@@ -437,6 +437,11 @@ class DocumentImpl : public DOM::Document_impl<stringT, string_adaptorT>,
       orphans_.insert(node); 
     } // orphaned
 
+	bool isOrphaned(NodeImplT* node) const
+	{
+	  return orphans_.find(node) != orphans_.end();
+	} // isOrphaned
+
     void purge(NodeImplT* node) 
     {      
       orphans_.erase(node);
diff --git a/include/DOM/Simple/ElementByTagImpl.hpp b/include/DOM/Simple/ElementByTagImpl.hpp
index d01827c4..26076195 100644
--- a/include/DOM/Simple/ElementByTagImpl.hpp
+++ b/include/DOM/Simple/ElementByTagImpl.hpp
@@ -94,10 +94,10 @@ class ElementByTagList : public DOM::NodeList_impl<stringT, string_adaptorT>
   private:
     void populate() const
     {
-			NodeListT dummy;
+      NodeListT dummy;
       nodes_.swap(dummy);
 
-      checkNode(rootNode_);
+      checkChildren(rootNode_);
 
       changes_ = ownerDoc_->changes();
     } // populate
@@ -116,11 +116,15 @@ class ElementByTagList : public DOM::NodeList_impl<stringT, string_adaptorT>
         if((tagName_ == node->getNodeName()) || (allNames_ && node->getNodeType() == DOM::Node<stringT, string_adaptorT>::ELEMENT_NODE))
           nodes_.push_back(node);
 
+	  checkChildren(node);
+    } // checkNode
+    
+	void checkChildren(DOM::Node_impl<stringT, string_adaptorT>* node) const
+	{
       for(DOM::Node_impl<stringT, string_adaptorT>* child = node->getFirstChild(); child != 0; child = child->getNextSibling())
         if(child->getNodeType() == DOM::Node<stringT, string_adaptorT>::ELEMENT_NODE)
           checkNode(child);
-    } // checkNode
-    
+	} // checkChildren
 
     typedef std::deque<DOM::Node_impl<stringT, string_adaptorT>*> NodeListT;
     mutable NodeListT nodes_;
diff --git a/include/DOM/Simple/NamedNodeMapImpl.hpp b/include/DOM/Simple/NamedNodeMapImpl.hpp
index 9cc02422..0dc1dad9 100644
--- a/include/DOM/Simple/NamedNodeMapImpl.hpp
+++ b/include/DOM/Simple/NamedNodeMapImpl.hpp
@@ -160,13 +160,14 @@ class NamedNodeMapImpl : public DOM::NamedNodeMap_impl<stringT, string_adaptorT>
       return nodes_[index];
     } // item
 
-  private:
+  protected:
     void throwIfReadOnly() const
     {
       if(readOnly_)
         throw DOM::DOMException(DOM::DOMException::NO_MODIFICATION_ALLOWED_ERR);
     } // throwIfReadOnly
 
+  private:
     typedef std::deque<NodeImplT*> NodeListT;
 
     NodeImplT* getNode(typename NodeListT::const_iterator n) const
diff --git a/include/DOM/Simple/NodeImpl.hpp b/include/DOM/Simple/NodeImpl.hpp
index 50b84224..aa43f1a9 100644
--- a/include/DOM/Simple/NodeImpl.hpp
+++ b/include/DOM/Simple/NodeImpl.hpp
@@ -416,8 +416,8 @@ class NodeImplWithChildren : public NodeImpl<stringT, string_adaptorT>,
       } // if ...
 
       checkCanAdd(newChild);
-      typename std::deque<NodeImplT*>::iterator result = findChild(oldChild);
       removeIfRequired(newChild);
+      typename std::deque<NodeImplT*>::iterator result = findChild(oldChild);
       *result = newChild;
       newChild->setParentNode(this);
 
diff --git a/include/DOM/Text.hpp b/include/DOM/Text.hpp
index 020d4ecf..a9c3d471 100644
--- a/include/DOM/Text.hpp
+++ b/include/DOM/Text.hpp
@@ -28,6 +28,8 @@ class Text : public CharacterData<stringT, string_adaptorT>
     Text(const Text& rhs) : CharacterDataT(rhs) { }
     explicit Text(const NodeT& rhs) : CharacterDataT(rhs, 0)  
     {
+	  if(NodeT::impl_ == 0) // null nodes can always be cast
+		return;
       typename Text::Type type = rhs.getNodeType();
       if((type != Text::TEXT_NODE) && (type != Text::CDATA_SECTION_NODE))
         //throw std::runtime_error("bad_cast: Cannot cast Node to Text");