Have you ever tried finding the easiest way to change your mouse orientation and you wanted to use a short-cut for it? I am sorry but it is not that easy to achieve it with one click, the best solution I found was to create a short-cut that gets you to the mouse setting and change it from there.
You can download the short-cut from here.
http://www.sevenforums.com/tutorials/143549-mouse-properties-shortcuts-create.html