Just keep in mind that Empower doesn't work all that well with any OS higher than 4.2 due to restrictions imposed by RIM. You probably won't see any sent messages and you'll have to hit escape twice to get out of it. You might want to pass the following link on to your BB Admin and see if he will do this. This procedure will put a mailbox icon on your BB for just your BES messages, just like your BIS mailboxes. View Document
Best of all it's free and works better than Empower.