Changing default printer in NT 4

I'm trying to change the default printer with Delphi 4 under NT 4. I use the
registry (writeStringProfile windows, device, and printer and a sendmessage
wininichange). It seems to work with W95 and NT3.5 but doesn't want to work
with NT4. It just deselects the current default printer but doesn't set mine.

Has anyone any clue about my problem ?

Thanks in advance...

David Metoz