This is from the remote users guide. COmplete guide can be found at:
If you want the Power Key to control multiple devices at once…
1. Press and hold the STB key.
2. While holding down the STB key, press OK.
3. Release both keys. The Device Keys will blink twice.
4. Press 9 - 7 - 7. The STB key will blink twice.
5. One after the other, press each Device Key you want the Power Key to control in the order you want them to turn on or off.
6. Press OK when done. The STB key will blink 3 times to indicate success in programming.
For example, to program the Power Key to turn on or off your TV, AUX and STB, in that order, with one press of Power, press [STB+OK], [9-7-7], [TV], [AUX], [STB], [OK].