You need specialist mixer for that. Ardupilot doesn't support it unless you write your own code.
Thank you matthew, could you give me any more info or advice on this?
Im surprised that the Crius has support for every configuration apart from a twin rotor! However i did have this niggling doubt that this could be the case and i may have to do some DIY.
The only option i could come up with, was to set up the Crius as a single rotor heli. I dont want to touch the code inside the Crius, i want to leave that as stock, but feed the servo outputs into an IOIO micro im using for other things. Im not using servo's to control the rotors, but stepper motors and mechanics.
Any tips would be greatly welcomed though.