Sharing Mounted Drive

I have a network with a bunch of computers (running windows media center 2005
and Vista and XP) I have used up all the drive letters (Yes AtoZ!) so I’m
using mounted drives which works fine but I can’t find a way to share the
ones on the Vista computer. I was able to share the one root drive on the
Vista Computer using the method listed here
(http://www.hardwarecanucks.com/guide...der-vista.html)
but that didn’t work with mounted drives. Any ideas would be greatly
appreciated. Thanks