Can you try to mock up this a bit easier?
(try doing/hacking on top of my MC demos - http://anonsvn.jboss.org/repos/jbossas/projects/demos/microcontainer/trunk/)
* two jars mocking your ejb jars
* third jar containing a service that would call a service from the first jar
The jboss-classloading.xml looks a bit wrong, but I doubt that's the real cause.
e.g. export-all=NON_EMTPY vs. capabilities, no need to declare parent-domain as default (that is done by default already)