Hmm, I will search more info about the reboot button. Looks like deep system button, so I am not sure.
With back button I mean this:
If you check the video what I posted above, there is bottom status bar with onscreen buttons. One looks like triangle. If you press it then it returns you one step back. In our case it closes dialogs or opens general settings. It’s important button.
The button what you describe is “Home button”.
Btw : I was able start smart watch emulator. The user interface has glitches, but overall look is usable.
In worst case I can add fixed button what will emulate back button.
Edit : Hmm I see that Sony Smartwatch 2 has this button