Howardcano, thanks for your advice! I just fiddled with the servo and driver for a bit and managed to get the driver to control the speed. The only problem now is that the driver is "off" when it is pointed to the middle (there's no click, which makes it hard to judge), and the click at the beginning of the driver still does nothing. If I used the other half of the driver, the servo reverses direction.

Still, as long as I can control the speed of the servo, I'm fairly content.

Thanks so much for all your advice! If you have any idea how I can set up the servo and driver so it clicks on and off, that would be wonderful.

Rebecca.