For another project we develop together with the guys from University of East London a plugin framework in ADOxx for developing custom XML export. The basic idea is that each XML transformation plugin is an XSL file that provides the transformation logic. Please find attached the implemented resource as a link to a forum post.
In this case a default set of transformation plugins can be provided within the library and additionally, the user can develop and provide new plugins as required.

Related Forum Post: http://www.adoxx.org/live/faq/-/message_boards/message/61668