Assistance with configuring a Fixed Wing with independent steering wheel

Hello PX4 team,

I would like to contact you regarding a project using a fixed wing drone with a specific configuration. This drone is equipped with a steering wheel located at the rear, controlled by a servo independent of that used for the rudder (rudder).

I would like to configure the system to meet the following requirements:

In manual mode: The steering wheel must be able to be controlled directly via my radio control, independently of the other controls.
In autolanding mode: The autopilot must take control of the steering wheel to ensure a precise and controlled landing.
I’m currently exploring the PX4 documentation and would like to know:

How do I configure this steering wheel in the PX4 configuration file to be independent of the rudder?
What are the recommendations regarding the mapping of radio remote control channels and their assignment in the software to ensure a smooth transition between manual and automatic modes?
Are there any specific settings or scripts to adapt for this type of configuration?
I am also open to any suggestions or additional documentation that could help me configure this system effectively.

I thank you in advance for your help and remain at your disposal to provide any additional information if necessary.