How to control a McNamum vehicle through RC using a rover frame with a custom mixer file

Dear all, Iโ€™m using PX4 v1.13.3 and want to use the rover frame to achieve RC
control of a McNamum vehicle with a custom mixer file.

Airframe: Rover Aion Robotics R1 UGV
Board: FMUv5

Now through a customized mixer file, I can control all four wheels of my vehicle, like moving forward, backward, and rotating around the geometric center, here is my mixer file:

M: 2
S: 0 2 10000 10000 0 -10000 10000
S: 0 3 10000 10000 0 -10000 10000
M: 2
S: 0 2 10000 10000 0 -10000 10000
S: 0 3 10000 10000 0 -10000 10000
M: 2
S: 0 2 -10000 -10000 0 -10000 10000
S: 0 3 10000 10000 0 -10000 10000
M: 2
S: 0 2 -10000 -10000 0 -10000 10000
S: 0 3 10000 10000 0 -10000 10000

But when I try to pan left and right on top of this and add a line like this:

M: 3
S: 0 0 10000 10000 0 -10000 10000
S: 0 2 10000 10000 0 -10000 10000
S: 0 3 10000 10000 0 -10000 10000
M: 3
S: 0 0 -10000 -10000 0 -10000 10000
S: 0 2 10000 10000 0 -10000 10000
S: 0 3 10000 10000 0 -10000 10000
M: 3
S: 0 0 10000 10000 0 -10000 10000
S: 0 2 -10000 -10000 0 -10000 10000
S: 0 3 10000 10000 0 -10000 10000
M: 3
S: 0 0 -10000 -10000 0 -10000 10000
S: 0 2 -10000 -10000 0 -10000 10000
S: 0 3 10000 10000 0 -10000 10000

I canโ€™t shift the car left and right with RC, should I customize a frame or something else?
As I am a beginner, this is very confusing for me. If you have suggestions on how to solve my problem, thank you very much for your reply, and please let me know if you need more information.

I once did a mecanum controller + simulation, you can try it if you want.

Just FYI, there is now a module dedicated to mecanum rovers that was added in this PR.