Asus graphic card V9560TD128 and DVI connection

Together with 3 other persons we bought a PC with an Asusu P4P800 DeLuxe
motherboard and Asus V9560TD128Mb Graphics card.
Bios and Videodrivers are the latest editions (Bios 1015 and Video
52.16). Also tried the latest NVIDEA drivers.
We are using Windows XP Professional.
The monitor is an iiyama H430 17" Flatscreen.
The monitor is connected to the graphics card with the DVI cable.
The default resolution of the monitor is 1280x1024.

Our problem is that with this configuration we cannot adjust the screen
to the resolution of 1280x1024. The maximum resolution will be 1024x768.
When connected with the analogue cable a resolution of 1280x1024 is
available.

We sent several mails to Asus and we also filled-out several forms on
their site about this problems, however, no answer at all from Asus.
One of my collegues already sold his card and changed over to another
brand. This appeared to be succesful.
Any help would be appreciated. Or if anybody knows how to get the
attention af Asus, that would be great also.
Until now they Asus gives no support at all.

Thanks in advance,

Carel