For your info:
We were able to solve this by isolating the Fear adding a jboss-app.xml and a simple loader-repository entry there.
In the F ear is a top-level lib directory with our xxx.jar version 1,0.
xxx.jar 2.0 is in the lib directory. The other ear's no changes.
The visibility of the CivisionSessionListener class is not solved yet (needed for Shiro single-signoff).
Could that be arranged with jboss-classloading.xml? Can you provide an example?
Besides this:
There were some plugin jars that needed to be outside the ear (must be customizable).
These were callable but could not talk back to classes inside the ear.
We were able to solve this by loading these separately using raw byte streams (nasty but effective).