I think I missread your initial post, but I in my missread I think I might be able to do it with a single throttle, the flip reverse.
Can you start and stop engines independantly? I think I remember reading that you can, tho I dont know the keystroke to kill or start engine 1 or 2 separately. I know kill both engines is E. Maybe shift-1-e to kill engine 1. Something like that.
Anyway, At the top of the manuever, to bring power off 1 and accentuate the yaw control to the left, just kill engine 1. Youd probably have to restart it again right away given the ramp up time, but I think it would have the desired effect of removing power from that engine.
A keystroke like that could be mapped to a button or hat on the stick to make the procedure easier while using a single throttle.
Think that might work?