Assigning Hotkeys to Mouse

[morosa]

I'm trying to use my <Button4> as Alt but it's not working! I'm wanting to use this button along with my 1-9 keys.

First, I tried to simply bind <Button4>+1 in the EQ2 Options but it will not allow the second key (1).

I tried going into my mouse settings and setting the keystroke for <Button4> to be Alt. EQ2 doesn't even recognize the button when I do this.

Any ideas of what I can do to get this to work, or if it's even possible?