You would be surprised how many great dog trainers there are out there that could help you keep the dog from doing this undesirable behavior, even if it is an older dog. Haven't you ever seen Cesar Milan the Dog Whisperer or "It's me or the dog" on NGTV or Animal Planet? I am blessed with a wonderful trainer in my area. She is amazing and can show you how to change behavior in a very short amount of time so it wouldn't be a problem any more. You should try to seek out trainers or animal behavior specialists in your area. Start with your vet and the internet. You will be amazed that with a little effort on your part how many bad doggy habits you will be able to stop. But it requires discipline, effort and consistency.