Don't know if this could help, but I noticed following (with same hardware):
1) booting on Ubuntu 10.04 (64 bits) Live CD, not intalling but testing:
I succeed to connect and configure an external monitor !
But with an installed Ubuntu, I have the same bug than Tim reported
2) installing Kubuntu 10.04 (64 bits):
I succeed to connect and configure an external monitor !
But when shuting down, the laptop freezes, and rebooting with external monitor connected also freezes the system.
3) Mandriva 2010.1 (64 bits) suffers the same issue than Kubuntu
Don't know if this could help, but I noticed following (with same hardware):
1) booting on Ubuntu 10.04 (64 bits) Live CD, not intalling but testing:
I succeed to connect and configure an external monitor !
But with an installed Ubuntu, I have the same bug than Tim reported
2) installing Kubuntu 10.04 (64 bits):
I succeed to connect and configure an external monitor !
But when shuting down, the laptop freezes, and rebooting with external monitor connected also freezes the system.
3) Mandriva 2010.1 (64 bits) suffers the same issue than Kubuntu