How to use Mouse Scrollwheel Left/Right buttons?

On my mouse if you tilt the scrollwheel to the left or the right it allows you to scroll left and right on webpages and other programs with a horizontal scrollbar as opposed to scrolling up and down by rotating the wheel up or down.

I noticed that the Input Manager and game launcher Input section does not even detect these buttons when I try to put them in as a usable key.

Is there a way (even a hacky way that would involve using some outside program to assign the left/right scrollwheel buttons to other keys) to assign and use these buttons while in game?



*Edit: I found this article on how to forcibly reassign those buttons:
http://www.howtogeek.com/howto/14400/use-those-extra-mouse-buttons-to-increase-efficiency/

but is there a way to get them to work in Unity without outside programs?

 

In the input manager, for any input, change the type to Mouse Movement, and change the Axis to 4th Axis (Joysticks). That should work