change mouse_button_modifier in ubuntu 12.10

[kustaa53]

hi,
Im trying to change the mouse_button_modifier to "Super" in ubuntu 12.10.
I used dconf-editor to change org.gnome.desktop.wm.preferences.mouse-button-modifier but it didnt affect at all.
Any suggestions?

thanks,
Kustaa

edit:
Im using gnome as my wm