Short answer: Implement org.CognitiveWeb.xpointer.ISchemeProcessor
The XPointer Framework is extensible. One of the very coolest things about this is that you can develop your own XPointer schemes that expose your application using the data model that makes the most sense for your application clients.
For example, let's say that you have a CRM application. The important logical addressing units probably deal with concepts such as customers, channels, and products. You can directly expose these data using a logical addressing scheme independent of the actual XML data model. Not only does this let people directly address the relevant concepts using a purpose-built addressing vocabulary, but this means that your addressing scheme can remain valid even if you change or version your XML data model. What a bonus!
The same approach is being used by the MindSwap laboratory at the University of Maryland to prototype a variety of XPointer schemes for addressing semantic web data