Camera trigger by RC Channel

Hi everyone,

I recently changed my Pixhawk 2 by a Pixhawk 4 mini. I had some troubles setting everything up but now it works. I chose PX4 firmware against Ardupilot because I like using QGroundControl.
I’m just facing a small problem :
With Ardupilot, it was possible to set an RC channel as a Trigger camera fonction. This way I was able to trig the camera with a radio button before my flights, just to verify that everything was working fine.
I wasn’t able to do the same with PX4. I managed to set the trigger pins and it works when I press the trig test button in QGC but I didn’t find a way to set an RC channel as another trigging possibilities.

Does anyone knows how to do that ? Do you think it’s possible in PX4 ?

Here’s my config :
Pixhawk 4 mini
Skydroid M12 Radio
Skydroid receiver/telemetry module
Also tried with my Taranis X9D plus and my X8R receiver
Trig servo (PWM)

Thank you really much for your help,
Kate.