Edit/Enable Extra Mouse Buttons?

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http://www.kubuntuforums.net – I have a blue laser MS Mouse with the side buttons. I can't see how to enable/edit the side buttons under the KDE system settings. My goal is to map one of the side buttons to the middle mouse button since I MMB clicking with the mouse wheel is difficult for me. Any advice would be appreciated. ps. I read somewhere about editing xorg files. Though I am not clear on this. pps. Yes I know its an MS mouse but the blue laser works well for my starcraft 2 addiction. :P (HowTos)