TwinView: detection of second monitor

[Thomas Kaiser (ubuntu)]

Hello All

I just got two new Acer TFT Displays (AL1715). Unfortunatly, I have to 
use a VGA extension cable to reach my box. But with the extension cable 
connected, the second monitor gets not recognized by Xorg. If I connect 
the second monitor directly TwinView is wotking.

The second monitor is connected to the DVI port with a DVI-Analog 
adapter. Is it possible to force Xorg to use this montior even it does 
not detect?

If I add the extension cable after Xorg is running in TwinView mode 
there is no problem with the picture, so the cable is OK. (The analog 
port has no problem with the extension cable and during boot I see the 
messages on both screens).

Or there are other ideas to make Xorg detect the monitor?

Thanks in advance, Thomas