What is the keycode for multitasking/appswitch for samsung galaxy s3?

Question

Our app is crashing (it says "application has stopped) after we longpress the home button on samsung galaxy s3 (the longpress button is used to popup the multitasking screen/app switch dialog) we do not have this problem on our another testing device htc evo 3d so what is the keycode for this "action" ? and how can we disable this function ?

This code sadly does not work:

public boolean onKeyDown(int keyCode, KeyEvent event) {
    if(keyCode == KeyEvent.KEYCODE_APP_SWITCH) {
        System.exit(0);
            return false;
    }
    return super.onKeyDown(keyCode, event);
}