How to change default printer under WinNT

Need assistance on changing the default printer under Windows NT 4.0,

I have written a function the will change the default printer under Windows
95 just as if you went to the printer folder, right-click on printer  and
checked Set as Default.

This function uses Enum printer, GetPrinter, OpenPrinter,  then
changing the attributes value in Printer_Info_5 structure to value of
PRINTER_ATTRIBUTE_DEFAULT then using SetPrinter to write changes.
Broadcast message of change to Windows.

When I run the same function in WinNT it works fine but does not make the
change.  Any ideas or suggestions??