I am not much familiar with how this can be done in JBoss AS 4.2.3. However, if you are willing to use JBoss AS 5.1.0, then we can point you to some of our EJB3 project code on how this can be done.
I'm very interested. It would be great to hear from you.
Thomas, sorry, this one is taking a bit of time. I can point you to multiple links spread across projects which probably won't make much sense. So i'm thinking of writing up a wiki with a small example which can atleast give you and others an idea of how you can use the EJB3 metadata through MC deployers. I'll post a link here, once that's done.
Thank you very much so far.