I am using a Blackberry that gets its mail picked up from the GW system
using IMAP via the service provider (bell.ca). It checks in for mail
every 15 minutes, picks it up and forwards it to the Blakberry

The problem is that it is only picking up new mail from the Mailbox.
If any mail has been moved to other folders because of GW rules, it
does not pick it up.

Does this seem right or is there some other problem ?

Also, If the mail in the mailbox has already been read, should the IMAP
function pick up this mail as well ?

Is there a better solution here other than BES ?