Since it says no class definition found error, it seems to be some sort of class loading issue. Is the local interface and the EJB in the same jar? Is the jar declared to be an EJB jar and placed at the top level of the EAR.
Probably best if you attach a directory listing of your EAR file and the contents of application.xml from the EAR.
In my application.xml (EAR plugin) I did add:
THAT WAS THE SOLUTION, IT WORKS!! :))
So those jars need to be declared as ejb:s and stated in application.xml, I thought it was enough to declare them as dependencies i maven.
Your hint really helped me.