Outlook folders

Ok the skinny - BES, 4.2 OS, 8700g devices. Ok, the question - I know there is a way to map the folders from Outlook's Cabinet or Inbox to the Blackberry through Email Settings in Desktop Manager. My question is to you knowledgable Crackberry gurus is once mapped (checked) and the device is synch'd, does it only show the latest messages placed into the folder or all messages (old and new)? My Director wants to start using this feature and when I tested it on her device, I can only show new messages or no messages at all. And she has lots of folders! Thanks.