If you have a mouse with more than three buttons, the Autodesk Architectural Desktop Customize User Interface dialog makes programming those additional buttons a breeze. No more assigning a menu action to a function key [by a reference to another menu item, for pop up menus like the SNAP menu], then opening up your mouse software and assigning the action to the mouse button. Now you can set a macro right in the CUI file.
Type CUI at the Command: prompt to open the Customize User Interface dialog. Expand the mouse buttons item and then expand one of the subitems: Click, Shift+Click, Ctrl+Click or Ctrl+Shift+Click, depending upon how you want to activate the macro. Click requires just clicking the mouse button, Shift+Click requires depressing and holding the Shift key, then clicking the mouse button, etc. Finally, select the button you wish to modify [or right click the the menu item to add a new button, and provide a name, description and macro in the Properties area.
The image below shows how I assigned the Object Snap Cursor Menu to my fifth mouse button. Click on the image to see a larger version of it.
Mouse Button 5 Macro