Tailsitter with differential thrust problem

Hi everyone
Iā€™m trying to use Pixhawk 4 with PX4 firmware as Caipiroshka Tailsitter airframe.
Lately I was trying to take-off in fixed-wing on a trolley.
But I couldnā€™t control yaw since thereā€™s no differential thrust operated.
Is there anything I can do to turn on the differential thrust on fixed-wing mode?