I could find no way to remap a button to a # to launch a game.
There is however away to enter any #.
At blue Select a game option screen:
Press Start to bring up text entry menu
then left trigger to rotate to #'s
Then diagonal D-Pad to upper left to select 1 by pressing a button
Press start to hide text entry menu.
Press Select or Start sometimes brings sound back.
If not reset from Select Menu.
Press Select, nav to exit.