Oddly enough just been looking at how to do finders.
Basically you need to put the finder 'SQL' in the jaws.xml, the jBoss specific descriptor file.
Following reference explains how to do it: http://www.jboss.org/online-manual/HTML/ch06s07.html
Looking at version 2.4.4, it appears it is only 1.1 compliant with some bits of 2.0 such as message driven beans. I think you will need to wait until JBoss version 3 to get full 2.0 compliance.
However I'm just starting on JBoss. Anybody knows better please tell me.