For mapping the mouse buttons you use numbers to refer to the buttons and scroll-wheel. I haven't been able to find a complete and well maintained reference for the mapping though.
The most complete thing I found was:
http://wiki.mbirth.de/know-how/softw...e-buttons.html
The buttons 8, 9 seem to be mislabelled/insufficiently labelled, because they function as browser back and forward.
Is there any (quasi)official source I could reference?