I am trying to do something similar (If I understand you right). I am trying to do a shadow of all the changes to a bean in a second table. This requires the extra sql during insert, update and delete operations. Anyway, I am close to getting a solution. I have posted a thread with my current problems if you want to want to contribute =)

thread:
http://www.jboss.org/modules/bb/index.html?module=bb&op=viewtopic&t=forums/