My first GSD did not like the bells. He also did not whine to go out so we put a driveway wireless alarm by the door.
This won't be to helpful, but all you can do is tell them no and show them where to go. Also try to take them out every hour or so and really praise them when they go outside.
With both my GSD's right when I thought they would never get it they just started going outside. Something just clicks. It took my first GSD longer. We got him at 8 weeks. With Kaleb it took about a month, but he was 3 months when we got him.
Riley - 11/05/2012-8/30/2013
He will always be in my heart.