I have the same display resolution and have had similar issues with not having it show up in the lists in the game. I personally don't handle the part of the code that takes care of this sort of thing, but I was told in IRC that such a resolution *is* (or should be) in the lists, but might not show up if the game doesn't detect it as one that your video card can handle.
If that's accurate, it means the game has a video card feature detection issue of some sort, which is a bug, and should therefore go in the bug tracker (when making a bug report, please reference (give a link to) this forum thread).