Oh yeah, don't scold him for growling. If you do, he may stop growling but then go straight for the bite with no warning growl.

I would praise and treat him lots if he ever doesn't growl. Find out where his comfort zone is (how close the cat can be to him and his bone without a reaction from him). Give him treats and praise and gradually move the cat closer. He may eventually associate the cat being near his bone to getting something good to eat.

I'll still look on the web for some advice though..