Found the problem! I had already checked that I had cglib in my classpath before but I made a double check now and it turns out my IDE had mixed up the classpath for some reason including an older version of cglib earlier in the classpath, still don't know where that comes from but anyhow it works now after rearranging it a bit. Cheers! /Andreas View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4019792#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...