Cubasis with Audio Interface problem

I’m using an Alesis IO4 Audio / MIDI Interface with my iPad. It has 4-channels. I’m using it with an official Camera Connection Kit.

Cubasis picks them up as two stereo pairs (Stereo Input, Channels 1+2 or 3+4). However, when I’m recording 4 mono instruments (with the IO4 switched to Mono) I need to be able to select mono inputs, not stereo.

I don’t seem to be able to select Mono Input, Channel 1, 2, 3 etc., only stereo pairs.

Has anyone had any success with their multi-channel audio interface yet? My interface works just fine in Cubase (Mac) and BeatMaker (iPad) so I know its not that which is the problem.