I recently put a bunch of users on a new domain complete with a new BES. (Blackberry Manager 4.1.4.15) It appears that when the users activated it only pushed emails from the prior 7 days. I have users that really want to get emails back 30 days. I changed the retention time but the users still aren't getting the old emails on their devices.

Any tips?

Don't think there is anyway to resend the old emails. I suspect you may have to wipe the BB, delete the user from the BES and re-activate for it to work.