I need to be able to demonstrate how Java API documents are created…

Hello Martyn,
Assuming you are developing with the Tamino API for Java (TaminoAPI4J) you can use any of the static constructor methods of the TXMLObject to create a new document. For example [where ?content? is a String containing valid, well-formed xml]:

TXMLObject xmlObject = TXMLObject.newInstance(content);

Once you have created a document object like this, you can insert it using the TXMLObjectAccesor’s insert(TXMLObject) method. You are recommended not to use the older Http Client API for new projects.
Does this help?
Regards
Bill