How to force resolution in VM instance?

Hi,

I wrote a script and needs it to run on 1360 x 768 resolution, but when running the game in a VM instance the game only allows me to select 1366 x 768. Why is that? Is there any way to force the game to run at 1360 x 768? I've tried editing config_material.txt and setting it manually but it reverts to 1024 x 768. I'm pretty sure it has something to do with my VM settings, since I could select 1360 x 768 in my main OS.

Thanks.