I'm sorry, but I don't really understand what you want me to do. I know the remote has audio buttons on the side, but I don't intend to use them because I am using a receiver for audio, not the TV speakers. In fact, the part of the pairing that asks me about music is kind of weird, and it won't let me get past that part unless I answer the questions. Worse, if I answer them in a way that Roku doesn't like, my only choices are to Try again or to cancel the pairing. Anyway, as it stands, I can do everything with the remote that I WANT to do except use the power button to turn on the TV or to turn it off.
As an aside, the Roku stick replaces Amazon's fire TV stick. Its remote also has a power button. That button worked fine, so unless there's a deficiency in the design of the Roku stick in this area, there should be a way to make the Roku power button work.
If you - or anyone else - has any additional suggestion on what to do, please do so in a very clear step-by-step fashion. Thanks.