Betaflight multirotor servo>2

[Dronard]

Hello,
I'm working on a concept of drone which is a Quad X with two independant motors and one servo.
My flight controler is a Matek f722 PX.
I have an auroraRC 50a ESC with his four motors wiring
I have a PBD matek f722 px w were I connect a servo on s9 and two esc on s5 and s6.
the servo is use to tilt the camera.
I think about set the two esc to servo output chanel.

I tried so many things: keep motors 1, 2,3,4 and disable motors 5,6,7,8 by {resource motor # none} and I set {resource servo 1 B00}{resource servo 2 B01}{resource servo 3 B06}. These B** corresponding to pins of s5 s6 & s9.

On Betaflight I've only two servo working : I can get the servo use for tilt and one of the two independant motors. I'm not able to have all.

I tried to set a pins connexion to pwm with { resource Pwm # B00 } it don't work...

Does someone know how to use 3 servo output independant of the quad X mixer?

[Dronard]