I posted this same post in the Kodi forum and had multiple replies however, I still think that there isen't a quick and easy answer, ever so frustrating as all the other devices I have set up on my Harmony one work flawlessly except Flirc xbmc.
When I got my Flirc initially, I have setup the Harmony One for Flirc and XBMC, worked OK apart from the back button.
Then I decided to upgrade the Flirc software from version 1.6 I think to the latest version 3.3 and now have lost the use of waking the Aus Chromebox from sleep and shutting it down, is there a way I can regain this back.
Somehow the back button on my Harmony One does not send a signal when pressed, can I add a button on the harmony software then get it mapped in Flirc GUI? or how should this work?
The sugestion given by wrxtasy #3 in the Kodi forum work pretty well, now the only thing missing is the wake and suspend, hope someone can help with this.