I was able to set my slider to zoom by first setting it to three bands, 100-80%, 80-20%, 20-0%. Then assign the numpad + key to one end, and the numpad - key to the other, leaving the middle empty. Zoom in and out is fast this way but still controllable. If it is too fast for your liking you could set it up as a macro and adjust the timing between keystrokes.
Hope that helps,
Last edited by Boomer; 07/04/09 01:12 PM.