Yeah I just wanted to run 2dsurround at 1920x1080 (games don't look too bad at 1920x1080 on the U2711 surprisingly). The other two monitors are G2410's which are also 16:9.
Ah ok, my bad, i thought "U2410", well 2D surround requires all displays must have a common resolution, refresh rate, and sync polarity.
As you can check in the pics you posted, the max preset display modes (common resolution) of the monitors you're running is exactly 1280x1024 (3 x 1280x1024 = 3840x1024, thats what you currently get).
Try to run the U2711 as single monitor and set it to 1920x1080, set SLI on. Turn off the PC, only then connect the two G2410, and then try to activate in NCP surround at 5760x1080, see how it goes.
You may alternatively try to use MonInfo and Phoenix EDID, you can find some info in these threads :
http://widescreengamingforum.com/node/13672
http://widescreengamingforum.com/node/14431