Though I have the later, I guess, STA-2700, that picture of the 2500 looks very similar.
I assume it was bought sans the remote, which if included, would take care of powering the receiver on and off.
As a possible fall back, I have been happily using several in some A/V applications around my house a nifty inexpensive RF based remote controllable single outlet power switch that I bought through Amazon..
The remote is key fob sized with a little removable key chain, and the remote switched 120v outlet is around the size of a older hefty non switching wall wart power supply and is supposed to be 15 amp rated, and it`s relay can be heard clicking when engaged with a manual power button that lights up when the outlet is switched on.
Just a back up/workaround incase suggestion.
Good luck with the endeavor.