Vista Printer Default Printer Issues

I recently got (3) new Vista Business Machines. My current infrastructure is
all XP SP2 PC on a SBS 2003 network. All my XP machines work correctly with
my HP printers, however when i add my Vista PC's to my network and add the
printer it never seems to set the default printer to the correct network
printer. If I add the printer and set the network printer to default...it
will save that setting however when my user logs off his machine or shuts
down the printer will get reset back to whatever printer it was set to first.
I have attempted to Clean all my printer drivers off the new Vista
Machines....and that doesn;t work. Does anyone have any solution as to why
the default printer setting doesn;t work like it does in XP?????