evdev, xmodmap & button mapping

[brian33x51]

I've got a logitech mx500 mouse. All the buttons are working and I've mapped all but the "switch one" which is button6.
However I'd like to map button6 to duplicate button2 since I hate the travel of the mouse wheel for clicking.

I tried

xmodmap -e "pointer = 1 2 3 9 10 2 7 8 4 5"
^
which failed pretty miserably since xmodmap didn't like the doubling up of the button

I also tried xbindkeys to send Pointer_Button2 using xvkbd but that also failed.

Any suggestions?