Running ActiveSync 4.5, Exchange 2007 and Treo 700wx

I would like to have two seperate folders for contacts. One for Work and one for Personal. I would like both folders to Sync with my Treo. I can only get the main default "contacts" folder to Sync, and cant' seem to find any options to select the sub folder "work contacts" under it. Any suggestions? Thanks for all the help out there!!!