Speeder's driver has been updated to support mouse scrolling. The script command to scroll up is "256d," and the script command to scroll down is "257d." I realize the "d" is somewhat counter-intuitive for the scroll up command, but it makes sense relative to how every other keypress works. Just think of it as if you are "pressing" scroll up.

Scroll up/down keypresses do not need to be released like other keys. For example, if you want F2 to scroll down, you would write
[113]
keys=257d
repeat=0

To scroll more than one "tick," simply repeat the command:
keys=257d|257d|257d

You can set repeat=1 if you want to scroll continuously as well.