Multiple monitors and XF86

Hi,

I'm using my PCG-R505DSK with Mandrake 9.1 and KDE, and am starting to get
it customized. I have yet to apply the relevant patches to the kernel and
all that, but I mostly use the machine at my desk, so ACPI isn't such a
priority (at least that's what I say until it melts).

What is a priority for me is being able to use an external monitor in
addition to the laptop screen, and to be able to set the refresh rate on the
external monitor to 100hz, while keeping the settings standard for the
laptop monitor.

The problem is that I don't know how to configure XF86 to do this.

Any tips?

Douglas Arellanes