Assigning port to loclhost on rover (14551) to communicate to qgroundcontrol not possible?

[makerprojects]

I am developing a rover with an Raspberry Pi using pymavlink to communicate to qgroundcontrol (qgc). When qgc receives a heartbeat from the rover, the qgc will respond to the port which Python arbitrarily assigns. I did not find a way using pymavlink as it is right now to assign port 14551 to the outgoing heartbeat of my rover. Maybe I am missing something here.

To keep my project moving, I changed mavutil.py by adding and evaluating an optional parameter when setting up the udp-connection to ensure the assignment of a specific port (see image - lines 1043ff)