Check if it has been added to the EJBQL BNF yet, it might be it is still in JBossQL definition. If so, send a bug report to SF so it will be addressed before 4.0 goes final.
This is true. JB4 uses new QL compiler. That, btw, supports besides queries INSERT, DELETE and UPDATE. But lacked ORDER BY. I added it recently for JBossDO ordering.
For CMP, I recommend 3.2 branch. It is more robust and feature reach at the moment.