Alright!
It worked.
My problem so far was that I sent out my "sensorData" as int-s instead of bytes. So now it Works.
But now, In windows, I get another problem.
The values that I put into JoystickReport->X range from 0-254.
It seems the values wrap around.
I'm testing with a potentiometer, and the values roll over from 0-63 in the windows testing screen quite a few times.
I'm not quite sure where to pinpoint this problem.