New harmony remote - Couple of questions

So i got my new mac mini and harmony remote today and i have a couple of questions.

I have setup the harmony one as plex media center on devices in harmony software.

1. I can only change volume inside xbmc when im in the menus, as soon as i start watching something i cant change the volume but mute still works.

2. I have changed the settings inside xbmc so that powertoggle means suspend. But how do i power the mac mini off/on

3. After i booted up xbmc now, i have this problem that if i press a button, the volume bar from osx is shown, and up/down/back/(any button) doesnt work, it just shows the volume overlay from osx ontop of xbmc

Nevermind i fixed everything expect one big problem, After xbmc wakes from sleep the remote dont work, i get the overlay from osx, anyone know whats what?

Hi,
One more thing. Make sure XBMC is powered on last in activity. And insert 1.5-2 second delay between XBMC and the previous device. First device should be your tv. That will ensure your screen is on when XBMC kicks in.