I think that the help we can provide over the internet is minimal. Since this beyond basic OB and is in the realm of behavior modification and rehab. Your going to need someone on site who knows how to read a dog, and prescribe a course of action.
If you want help over the net. Your going to have write down as much information as possible. Honest and througho are the only things that will matter. The more you write down the better. With a situation like this, you need to give the long version, not a short little blurb
I believe a dog's finest hour, the greatest fulfillment he holds dear, is when he has worked his heart out in a good cause and lies exhausted on the field of battle-with a ball in his mouth."
The real question is who and why is the dog biting, It sounds more like a socialization/fear issue. A behaviorist that practices positive techniques should be consulted to see what the circumstances are around the dogs behavior, and start a rehabilitation program.