Mueller Me joystick assigning functions

I've got the above joystick connected up in a T7 along with a Kuhn rake but I'm having issues trying to assign the functions to the buttons.

I'm not sure if there's a setting somewhere I haven't got right or I'm not pressing something. I've tried changing everything that I can see but it makes no ods. It's loaded on the VT settings screen and the functions are there to be assigned they just won't go onto any buttons I press!

I've checked AEF and there's 2 versions of the joystick but...

Mueller Me joystick assigning functions