If you are baffled because your BES email and their BIS email are showing in the messages icon and they want to have them separate, I have a workaround for you.
First go to Messages Icon
Press Menu Key
Go to Search
Under Service select the email account they want to view separately
Press Menu
Select Save
Put in a title and set up a Shortcut key (Example, AOL, shortcut key: A)
Press Menu and Save
When you enter your Messages folder, hit the shortcut key A and it will show you only your AOL emails. To view everything again hit the RETURN arrow.
It will take you right into your search to go back to your full inbox just press your back key (escape key).
I should get me a blackberry but I have to much fun with my AT&T tilt.