Trike
This is how I did it. I used a hub that has a freewheel on one side and transfers to a solid sprocket on the other side for the peddle chain, I then used adapters that "set screw" to the axle and attached all my solid drive sprockets to the axle. The pic doesn't show the hub very well at all, But you can get the idea anyway. An example of the type of hub I used is at e-bay item # 230486506486. Then just run the motor chain straight to the axle. So, in order from left to right, It's the motor chain(solid mount,)peddle chain(another solid mount) then the disc brake setup. Hope the pic helps some.
Shiney Side Up,
Big Red.