I have Vaio VGN-C240E, w/Intel 945 Integrated video,
Installed Kalyway 10.5.2/w gma950, worked on external monitor, and internal(if external was connected while boot, then disconnected). Both displays appeared in mac system info. Was able to set 1280x1024x32 on external (syncmaster tft) and 1280x800x32 on internal lcd. Unstable behavior.
Then after installing 10.5.3 combo update + 10.5.4 apple update - worked only on external, and it was the only display detected by macos.
No additional drivers installed. Then added magic string to Boot.plist