Actually there is 1 way to disable background still.
Firstly running darkorbit on a computer that supports its 3d feature.
then after and logging out and stuff
i run darkorbit on a computer that doesnt support 3d, but still the game loads in 2d but with 3d options in display->advanced mode, for eg, anti aliasing, textures, lightnings, etc
when i put the settings on low now, no more background in 2d mode

hope that helps.
ps: been botting with that this whole week from s bot as well. event boxes from pet looter of course, does glitch a lot since the new version