F11: Why is Xorg failing to allow 1600x1200 resolutions?

[Daniel B. Thurman]

On F8/9/10, I was able to drop in my xorg.conf
file into /etc/X11 directory and was able to get
the X display to recognize the Monitor type and
get 1600x1200 resolution, but for some reason,
I am not able to do this with F11.

My montor is a Hitachi CM715, and my onboard
video is an Intel 82945G/GZ Integrated graphics
controller.

I have tried system-config-display & it seems
to limit my resolution to 1280x1024.

How can I resolve this problem?

Thanks!
Dan