Start/Home button press identification and Handling windows phone8


I need help. I am developing an app for windows phone8 and i want to add a functionality to it on Start/Home button tap on device. I need it to complete a particular set of operation before leaving for that i need to know how to find that button. i can get the back button but i need home button too. Please help me out on this.

Not sure if you can get Start/Home, but you can still make some use of OnApplicationFocus and OnApplicationPause