Resolution glitch

Hei.

The problem is. If i try to play in 1280 x 800 or any other 1280 x xxx it always goes in game to 1280 x 960 and not the resolution i requested… ! So i got black stripes on up and down of screen. The native screen resolution is 1650 x 1050 wich is 16:10.

I guess an error of some kind. Any way to force it to 16:10?