Windows Phone 8 - OnApplicationFocus

Hello!

I want to save the game if the game lose the focus (because the player can close the app this way, and the values of all the variables would be lost!).

I use Easy Save for this.
My phone ignore “OnApplicationFocus”. What should i do to handle that? The scripting reference gives an example about it.

I tried using this:

OnApplicationFocus(bool focusStatus)
{
if (focusStatus == false)
{
ES2.Save(valueCounter, “SaveFile.txt?tag=valueCounter”);
}
}

My windows phone ignores it and still doesnt save it if i lose the focus (holding the back button to the overview and closing on X).
I also tried OnApplicationPause but he ignores it too.
Which way do you handle that problem?

Thank you for helping
Greetings

I tried it to let the application “run in background”, but its still no solution for this problem.
Any other ideas?