Triggering camera in HITL simulator

I would like to ask about possibility of sending trigger signal to HITL simulation. I edited so I can communicate with my VTOL simulator. I use ctl_x parameters in updateActuatorControls method to get actuator values. These actuators are maped to main mixer. Camera trigger uses AUX pwm when pixhawk is in normal mode. Is it possible to map camera trigger to main mixer? Or is there other method how to get camera trigger PWM into ctl_x parameters?