did you add it to your ejb-jar.xml? Bill's book has examples on how you add them to your XML descriptor. I use this custom interceptor stuff with JBoss EJB3 and it works wonderfully :)
Actually I don't have an ejb-jar.xml file. I'm trying to avoid xml and use annotations for everything instead.
From the book I was under the impression that xml was not necessary to do this, at least that's what I understood from the last page in the "Interceptors" chapter. Thanks, anyway.