Try setting-up your timer on the DirecTV receiver to record that channel number (720) on Sunday starting at game time and ending an hour after it would normally end. If the receiver takes the timer program, you should be fine and when DirecTV turns on that channel, your receiver should pick it up.
Not too sure if this will work with your reveiver. I've had several over the years and it works with some but not with others.
They apparently turn these channels off and on for certain events and I assume it's to save bandwidth.
Good luck!