I know that you don't have my exact equipment, but your ideas (other than "buy other equipment") are welcome none the less.
Receiver: Yamaha RX-V363. Brand new from BB.
SP3 as my blu-ray player.
TV: Panasonic TH-42PZ80U
Cablevision Magnavox DVR.
HDMI from both SP3 and DVR to TV.
Optical from SP3 to V363's CD audio input jack. Scene 1
COAX from DVR to V363's DVD audio input jack. Scene 3
Would like to use the V363 remote control to control the TV, DVR, and receiver.
TV - volume and input source
DVR - channel, and stop, rewind, play
I would like to use the TV button on the remote to control the TV, and the DTV/CBL button on the remote to control the DVR.

Receiver: Yamaha RX-V363. Brand new from BB.
SP3 as my blu-ray player.
TV: Panasonic TH-42PZ80U
Cablevision Magnavox DVR.
HDMI from both SP3 and DVR to TV.
Optical from SP3 to V363's CD audio input jack. Scene 1
COAX from DVR to V363's DVD audio input jack. Scene 3
Would like to use the V363 remote control to control the TV, DVR, and receiver.
TV - volume and input source
DVR - channel, and stop, rewind, play
I would like to use the TV button on the remote to control the TV, and the DTV/CBL button on the remote to control the DVR.