The Pronto Hex you've listed is RC5 device 0, function 61, which should be discrete Off, not On. The documents linked in the link you've provided say this won't work if CEC is enabled, apparently. So try it with CEC disabled.
Power On is supposed to be RC6 device 0, function 63
0000 0073 0000 0015 0060 0020 0010 0020 0010 0010 0010 0010 0010 0020 0020 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0020 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0BE1
I think this should work even if CEC is enabled.
