Mark,

...but have you connected the user/workstation to the domain?

So... I don't know! ;-) XP is a little bit complicated...
I use the assistent "network ID" (from control panel, system) and all works fine for few (about 5) minutes... In this little time, I could add the users from the domain... When I restart the computer, I just see the users from the client (XP) ... I don't know why... I'm still studing it...

Any suggestion?