Pixhawk 4 Holybro / Mission Planner auxiliary channels

I bought Pixhawk 4 and was able to connect to Mission Planner, everything seems to be working fine, the problem is in my auxiliary channels, I can see and calibrate using sbus, but I can not assign the functions available in Mission Planner, does anyone know how to solve it?

Your description is not adequate to answer.
https://www.rcgroups.com/forums/showthread.php?2852885-Controlling-external-devices-like-Gimbals-and-Lights-with-a-Pixhawk

Thanks Mike for the answer, I’ll try to explain better:
It is a Pixhawk 4 connected to Power Management with the I / O PWM OUT connection, in connection with the Taranis / X8R I am using the SBUS connection on the DSM / SBUS RC port of the card.
I have all the functions set up and running on the Mission Planner, including 6/7/8 calibrated flight modes and auxiliary channels. The problem is that when I enter the Extended Tuning function of the Mission Planer the “Opc7” and “Opc8” fields are disabled, leaving no function assigned to any of the channels
What can it be?
Sorry for my English
Thank you

Problem solved with the new version of QGroundControl 3.5, ArduPilot Support for ChibiOS firmware connect and flash.