Note that Mark's code is really used for a joystick that twists (the kit joysticks don't).
If you have a joystick that doesn't twist, you usually program 2 buttons to rotate the robot in different directions (you may have experienced this concept in video games, where the rear controller buttons rotate the vehicle/whatever you're in).
If you want to do this, you basically test both buttons and send different values to that Rotation terminal based on which button is pressed, if any. Doing that might get complicated, so if you can't figure it out, feel free to post back or
check out this recent thread that is very similar. They talk about controlling a motor with two buttons.