How to extend Code Inspector checks?

An article on the ABAP Code Inpsector in the SAP Professional Journal last year stated that "...extensible checks.." would be supported by the CI. Does anyone have more information on that? E.g.:

1) What versions of WAS will support implementation of such extensions? I have Mini WAS 6.10 installed, and can see no [apparent] way to extend the built-in checks.

2) Is there any documentation available on how to make such extensions?

3) Does anyone have practical experience making extensions that they'd like to share?

Thanks...