Ironfist is right. There is also a registry hack to enable prepopulation when switching devices, not just on brand new accounts. You can also prepopulate subfolders by choosing them for redirection before activating the device.

I am hoping with the new full mailbox search feature in 4.1.5 that I will no longer need to explain to my users that the BlackBerry originated from a pager device, and is not a full replica of the mailbox, it is for on the go access to recent messages.

As it is right now at least I can tell them about the mailbox search feature coming in the next release. It is always difficult to say "nope, not possible, not going to happen" to someone who is difficult to begin with!