2560x1440 @120hz support?

[Gyponator 0]

So I have a Qnix QX2710 monitor, which is a 2560x1440 display, and I have overclocked it to 120hz (and yes it's all stable, works fine in desktop and other games and has been validated with high speed video to be not skipping frames), but when I try to enter these settings into the hardware_settings_config.xml file, the game reverts back to 1280x720 at 59hz. I tried setting it as read only but it still didn't work. I was wondering if anyone has any suggestions as to how I could get it to run at these settings

Usually when games don't work it's an API issue (DX10 and below don't support this res/refresh combo), but DX11 usually works! BF4, AC3, Splinter Cell Blacklist, Assetto Corsa and even GRID 2 all have no problem with it, so I'm a little confused.

Any suggestions welcome, all help appreciated

Thanks!