I have a Pioneer Elite PRO-1130HD plasma TV and scrolled through all of the commands on the LCD looking for a command that sounds like it might turn the speakers off, but unfortunately cannot find one.

Under Activities > Watch a DVD, I looked through the Settings, Troubleshoot and Custiomize Buttons and could not find a way of adding a TV "mute" command to the start of the DVD Activity.

How do I add a command (like mute) to the DVD activity?