This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
You will see there are constants defined in the interface that indicate what type of Node the implementing instance will be. These are commonly defined XML node types and each will be treated differently according to XML specs. If you are creating a text node and trying to add that to the body of your envelope, the Axiom framework will rightly treat it as plain text containing characters that must be escaped according to XML specification.