EDI X12 Standard implementation in webMethods

I have been requested to implement a EDI X12 4010 validation routine for incoming EDI810 files (invoice files) and I need to better understand how webMethods implemented its version of the X12 standard.

I am currently using webMethods IS 4.6 and I am familiar with the webMethods EDI Module (Core Component - v4.6). I also know that we should be using the service pub.schema:validate and I did some tests to see if it works and it does work. Now, I need help to better understand the way webMethods implemented the X12 standard using schemas.

Question: does anyone have a document that explains how webMethods implemented X12? Is there any document that shows all the document types implemented by webMethods (schemas & templates) and how to read them? Any ideas?

I am looking for something better than the EDICoreUsersGuide.pdf.

Your help is greatly appreciated!