Really, I've found the Modes option is rather meaningless ... xserver seems to ignore it in most cases.
After running 'xorgsetup', try adding
Code:
HorizSync 60
VertRefresh 75
to the "Monitor" section of '/etc/X11/xorg.conf'
... these are my values, so if your monitor comes with a manual look them up in there. The refresh rate here is 75 Hz, Sync is 60 kHz.