I have never played IAF. Since no one else had come up with any answer for you, I can try with my general knowledge of other Jane's titles I have flown. From that experience I had found that the rudders have to be counted as a single controller with the joystick either physically wired together to 1 input, as most TM's had, or through a device management system, such as CH had. The title software was not written with multiple input devices in mind at the time.