[114Klutz]

What are you attempting to do? Do you want the joystick to control the position of the arm, or do you simply want the joystick to control the speed of the arm movement?

If you want the joystick to control the position of the arm, you'll need a PID loop and a way of calculating where the arm is using the encoder. You'll also have to ensure(Unless its an absolute encoder) that the arm starts at the same position every time.

If you want to control the speed, then you'll still need a PID loop

Feel free to talk to me on aim (evil666rat), I'll be happy to help - I'm the programmer who wrote the code controlling our arm. I'll be happy to build some for yours, if you'll contact me with some more details.