ATI Technologies, Inc. RV370 5B60 [Radeon X300 (PCIE)]
thats the string in the xorg.config
SubSection "Display"
Depth 24
Modes "1280x1024" "1024x768" "800x600" "640x480"
EndSubSection
that is the display configuration as u can c 1280x1024 is there
default depth is 24
and this is a section from the xorg log file /var/log
(II) RADEON(0): Supported VESA Video Modes:
(II) RADEON(0): 720x400@70Hz
(II) RADEON(0): 640x480@60Hz
(II) RADEON(0): 640x480@72Hz
(II) RADEON(0): 640x480@75Hz
(II) RADEON(0): 800x600@60Hz
(II) RADEON(0): 800x600@72Hz
(II) RADEON(0): 800x600@75Hz
(II) RADEON(0): 832x624@75Hz
(II) RADEON(0): 1024x768@60Hz
(II) RADEON(0): 1024x768@75Hz
(II) RADEON(0): 1280x1024@75Hz
(II) RADEON(0): 1152x870@75Hz
it looks like it is supported