I have the same problem with ILA in 737 - 500. I have seen on youtube tha it is (at least was) working, so using APP was possible, but not now. I did ask support for it and they told me to check manual to this game. It was very usefull answer.
I had this problem, and it is pai in the ******, especially when I am using VR. Of course with joystick dropping I am loosing keyboard as well. So I have to turn off the game and on again, the I have to be lucky enough to have my joy working (even if detected and recognised in game).