This posting is older than 6 months and can contain outdated information.
I have not had a chance to try to set up the Harmony Smart Remote with a setup involving several devices, so the following is more or less a guess at my part.
Chances are that, when you add a device to an activity, the Harmony software tries to be smart about it and assign particular keys to particular devices automatically.
You should be able to select the commands of your choice for the buttons on your remote the same way that you'd use in the section "Unlocking all buttons of the Smart Control" in this blog post:
https://www.iospirit.com/blog/article/184/-/
For a complete overview of what command you'd need to assign to a button to send it to Remote Buddy, the table in this FAQ should help:
https://www.iospirit.com/support/faqs/remotebuddy/category/23/Hardware-Harmony-Smart-Control/entry/265/-/
To my understanding, Harmony will send power on and power off commands to the devices in an activity depending on your settings in the respective part of the app. You might have success by tweaking the settings mentioned in "Tweaking power settings" in
https://www.iospirit.com/blog/article/184/-/ (again)
(but this time for your TV and receiver).
You may also find additional help in Logitech's support resources for their remotes, including forums, a knowledge base and direct customer support at http://support.myharmony.com/ .
Hope that helps.
Best regards,
Felix Schwarz
