1 Create Seam ear project (SeamEar)
Target Server: JBoss AS 4.2
2 Run server
3 Run Project using Run As->Run on Server

The project will not start. Look at rhdevstudio\jboss-eap\jboss-as\server\default\deploy\SeamEar-ear.ear. There is no SeamEar-ejb.jar inside.
After removing project from server and adding again using Servers View SeamEar-ejb.jar will be created in deploy folder. So the project can be started.

But:
If you Create Seam ear project and run Project using Run As->Run on Server without start server separately the project will start properly.