I have a TabActivity and want to catch and handle presses of HOME and BACK. Where do I need to catch these events?

In my subclass of TabActivity I implement the following:

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    switch (keyCode) {
        // Code handling
    }

    return super.onKeyDown(keyCode, event);
}

Didn't work.

So I placed a breakpoint on the switch statement line. But this function never gets called, whether I press volume up/down, menu, home, or back. Where do I need to catch these KeyEvents?