clone displays work dvi

I have an Acer TravelMate 8104 notebook with a DVI output for an external monitor. It also have a VGA output. I have installed the latest ATI driver for the December CTP of Vista. When I try to clone the displays (display main desktop on both) it doesn't work with the DVI output. Then only the "Extend Desktop" option works. When I connect the external display to the VGA output, I get can "Clone" displays to work.
Does anyone know how I can get "Clone" displays to work with DVI?
Olav

I believe that there are issues surrounding dvi output with the december CTP, I had to go back to VGA in the end. But hopefully the next release should have resolved that.
Scøtt http://wlm.scottisafool.co.uk/
Olav Tollefsen wrote:

I have an Acer TravelMate 8104 notebook with a DVI output for an external monitor. It also have a VGA output. I have installed the latest ATI driver for the December CTP of Vista. When I try to clone the displays (display main desktop on both) it doesn't work with the DVI output. Then only the "Extend Desktop" option works. When I connect the external display to the VGA output, I get can "Clone" displays to work.
Does anyone know how I can get "Clone" displays to work with DVI?
Olav