Trouble programing Auto/Pilot button on Joystick

I have a Logitech Extreme 3D Pro joystick. I was surprised all my buttons but one worked, including spoilers and reverse thrusters, just fine on my first flight; however, my A/P button will not work. I have gone through the CDU Keyboard Commands, but have not found an A/P On/Off Command. I did at least find a Command to disengage the A/P. As I understood the instructions, I was to type Z in with my PC keyboard. This did not work. I'm wondering if there is a place somewhere where I have to enable my keyboard to connect with the CDU, and second, how can I make my joystick button turn the A/P On as well as Off. Any advise is appreciated. By-the-way, this aircraft flies as smooth and solid as can be. Thanks, Mike Nicholson