Add new keybindings

Add to gnome-keybinding-properties (an app of gnome-control-center) the feature to add custom key bindings using new keyboard layout.
For instance, my genius kb-21e keyboard has a 'word' key that I want to bind to OpenOffice.
The gnome-keybinding-properties recognizes the code of the key, but I cant add a bind to another action or application besides those in the list.
There is a bunch of apps that allow do that but, in my humble opinion, gnome-keybinding-properties is an easiest solution, but needs new funcionality.