Help: Span in Different Resolution

Hey /tech/, how you doing? Can I get some help?

tl;dr - How do I make my nVidia desktop use both a 1680 x 1050 display and a 1280 x 1024 display at the same time at their native resolutions?

I recently got a new monitor, a nice 1680 x 1050, and I'm trying to span it with my 1280 x 1024. I have managed to do this quite easily with my laptop (It's monitor is also 1680 x 1050) and I have gotten it to span with both the new monitor and the old one. This is all good, but the kicker here is that even though my laptop can span properly with my old monitor and a 1680 x 1050 display, my desktop fails to. When my desktop does a span, it forces both moniters to be 1280 x 1024 and then it spans fine, but I loose all the nice resolution of the 1680 x 1050 display. I believe that the difference is that my laptop is using an ATI card with ATI drivers to do this trick, and that my nVidia card (MSI GeForce 8500) is using nVidia drivers that don't understand what I'm trying to do. My question is, does anyone have a fix for this problem?

I have an update on my situation. BF2142 has decided to refuse to work on the new monitor, more on this after I kill myself.

Nvidia control panel -> Display -> set up multiple displays -> select primary (as new monitor). If this doesn`t help try swapping the monitor cables around and reinstalling the monitor drivers - BF is probably going for the first monitor which happens to be is the smaller one. Maybe try Ultramon - very handy multi-display software.