There is not a way to synchronise up folders to the device I'm afraid. This was only added in later Pocket PC releases, and never came to a formal H/PC Platform release.
There is a way to sync multiple contact repositories, however with the inbox, you're stuck when using the default toolset.
http://www.microsoft.com/downloads/details.aspx?FamilyID=2D31C7F0-B871-49CE-9F96-712A1695E372&displaylang=en