VTOL tricopter

First of all apologies if this is not in the correct subforum, I didnt see really where to post questions about the beta firmware or VTOL’s.

Im working on a tricopter VTOL with dual yaw. Two motors on the rear, both of which can be tilted (~150 degrees), a single ,fixed motor up front. The idea is to use differential tilt on the rear motors to obtain yaw in multirotor mode, and optionally, use it in forward flight as thrust vectoring.

I just downloaded and installed the beta firmware with VTOL support, but am I right concluding a setup like that is not currently supported? If so, is there any way to make this work, by writing a custom mixer?

Ive glanced over this page:
pixhawk.org/dev/mixing

I dont pretend to understand it (at) all, I’ll need some more studying, but right now im just trying to figure out if this can work, otherwise ill have to redo some design.