CyberMicha
have a look at this wikipage: MediaPortal/Configuration/General/KeysAndSounds - MediaPortal Wiki Documentation
there you can configure the Keymappings. Add a mapping for Action_previous_chan and Action_next_chan (I don't know now the exact name, as I'm not on my HTPC) there you can assing the chan +/- buttons.
For the back button add the Action_previous_menu and assing it to the back button.
have a look at this wikipage: MediaPortal/Configuration/General/KeysAndSounds - MediaPortal Wiki Documentation
there you can configure the Keymappings. Add a mapping for Action_previous_chan and Action_next_chan (I don't know now the exact name, as I'm not on my HTPC) there you can assing the chan +/- buttons.
For the back button add the Action_previous_menu and assing it to the back button.