GF3 Ti 500 DVI out - Detonator XP problems

Hello. I want to connect my Visiontek Xtasy 6964 card (GF3 Ti 500) to an Infocus LP130 projector using the DVI out of the card. I plugged the DVI cable with the PC and the projector turned off, and started the projector and then the PC. Once in Windows, I tried to change the output device from "analog monitor" to "digital flat panel", but the latter option was grayed out. I clicked in the "detect displays" button, but it didn't do anything.

Next, I rebooted the PC with just the DVI cable connected. To my joy, the projector showed the Windows 98 SE startup screen, but as soon as it entered to Windows the image was lost. I had to reconnect the CRT to see the desktop. And the "digital flat panel" option was still grayed out.

I tried installing the basic Windows VGA driver and I managed to see the windows desktop with the projector; but when I reinstalled the Detonator XP drivers (first the official 29.42 and then the leaked 29.80) the DVI out ceased to work again.

By the way, the TV-out works perfectly.

Can anybody help me?

Thanks!