Did some more researching. I think it is the "TransactionManager not bound" issue described in http://jira.jboss.com/jira/browse/EJBTHREE-771 So basically, embedded EJB is broken on Tomcat since RC9. Seam uses RC8. Gavin filed a problem about the RegisterSync problem (EJBTHREE-584), which was fixed in RC9. I updated the above mentioned 771-ticket, and also cross referenced it to Gavin's 584. Hope this will get people working on this. @Anybody who wants this fixed - I guess it´s time for some voting on 771 now. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3991629#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...