ATI x1950xt and and multi-screen support

[SCar222]

Hi,
I have and ATI x1950xt and 2 20' monitors. I have been trying to enable dual screen span on these, so I can play Command and Conquer 3 with the resolution 3200x1200. So far I've had a few good tips, but no luck.
I have installed UltraMon and tried the shortcut hack -xres 3200 -yres 1200, but nothing here either.
Will I need a Geforce Nvidia card to be able to have horizontal span, or does anyone out there know a method for achieving this with my ATI card.

Best regards,
Sean