It's NEC:130.93 function 4. MakeHex can certainly generate all 256 commands (or functions) for this device (130) and sub-device (93)combination.
I did find a ccf file for an AV10 that shows "Off" to be command (function 66) but I didn't see an On command. So you might try that. If the Off does work but you can't find an On command a macro for Off+Power toggle will act a discrete on.
Here are the commands someone else found for the AV1:
NEC:130.93 AMP/Tuner
004 Power 005 Vol + 016 Vol - 003 CD 008 Tuner 010 Aux 018 Tape/Monitor 000 DVD/5.1ch 001 Video 011 VCR1 007 VCR2 012 Mute 095 Seek down 094 Seek up 093 Preset down 092 Preset up 088 Vol FM/TV 089 Vol AM/Video 090 Shift 012 Power-Tuner
NEC:103 CD/DVD/LD Section
193 REWIND 199 FFORWARD 194 BACK 1 TRACK 200 FORW 1 TRACK 219 RANDOM 197 STOP 203 PAUSE 198 PLAY 144 PRIOR CD/DVD 143 NEXT CD\DVD
NEC:92.161 Tape Section
013 REWIND 012 FFORWARD 022 PAUSE 021 PLAY 020 RECORD 023 STOP
Good luck and make sure you let us know if you find discrete power commands.
