Hmm. This approach worked relativly good for me, I just avoided 
copying the hibernate libs into the server's lib directories by 
packing them into the '.sar'. 

However, when I restart the JBoss server, the hibernate service will 
not initlialize, because the the datasource I've configured isn't 
loaded at the point the '.sar' is loaded.
After this happend, the only way to get the hibernate service running 
again, is to re-deploy it. :-/

Is there a way to configure my hibernate service in a way that it only 
initializes AFTER the datasource is ready?

thanks for any comment,

J