First of all you will not find a single code that does both ON & OFF power of the receiver. Reason is that yamaha use of a wo-key poweer scheme, and add to that the lone power key on the directv remote. One of the commands will always be missing.
The volume keys NEVER initially with ANY audio code, reason is that the volume keys won't work at all without a tv code programmed t the tv device. Once there is one, the tv volume is now in the way, but that can be remedied.
So just use yamaha code 30176, with tv code in, to get the volume in just one device:
1. av1 or av2
2. press and hold MUTE & SELECT for two blinks
3. enter 9 9 3
4. press VOL DOWN
If you want the yamaha volume in ALL devices:
1. av1 or av2
2. press and hold MUTE & SELECT for two blinks
3. enter 9 9 3
4. press SELECT
You can test the other yamaha codes to see which one suits you best.