Scrolling projector display with ATI video on FC1

[ehemdal at townisp.com]

I use my Dell Latitude D600 for presentations and have recently been
unable to set the projector to anything but 640X480 resolution, regardless
of how the display resolution is set (1024x768 is the native res on the
display panel).

But instead of seeing the entire screen, the projector display acts like a
viewport.  As I move the mouse around, the picture on the screen moves
around to display, effectively, "what the pointer is looking at".  The
effect is dizzying, to say the least, and really unworkable.

Hardware is ATI Radeon Mobility M9, and all Fedora updates are applied. 
I'm using the 'radeon' driver according to XF86Config.  The system dual
boots Windows XP, and the Windows side of the house has no issue (the
projector pops to 1024x768 and displays the entire screen area).  I've
seen this happen with three different projectors, so I suspect the issue
lies with Fedora and not the hardware.

I've checked the archives, and I've seen references to fixes for a
projector stuck on 640x480, but none of the posts seem to address the
viewport behavior, which is really awkward.  I might have misread or
misunderstood something.  I'd like to get the resolution above 640x480.

Does anyone know how this can be done?   Thanks.  Erik