Session replication doesn't work in WELD using JBoss AS 6.0.0.M2. More description how to run weld-numberguess example in cluster is in linked issue (except using JBoss AS 6.0.0.M2 instead of 6.0.0.M1).
Additional tested configurations:
1) JBoss 6.0.0.M1 updated with current trunk of WELD (works fine !!)
2) JBoss 6.0.0.M2 updated with current trunk of WELD - doesn't work, after going to second browser to test session replication the application starts from scratch and doesn't continue with current session. The jboss AS's console doesn't output any error message
3) JBoss 6.0.0.M2 updated with WELD 1.0.1 CR2 - the same as 2)