Find other people you know that like dogs and are willing to help you out. This is a breed that loves the family but all dogs love food and rewards, so get others to reward him under your strict supervision. They can throw a ball, give the dog's favourite food rewards etc. Start off with acquaintances and then move toward total strangers. They don't necessarily have to touch him, just interact with him or work with him. This will teach the dog that good things come from others.
Try bringing his breakfast to a dog park and get others (acquaintances then strangers) to give him the food. Be very aware of the dog's behaviour but the fact that he hasn't growled before is good.
Another good tactic is an agility course where there are tons of people around. Other participants don't have to touch him just interact with him. So many pet owners stop courses after basic obedience. EXTRA courses are GREAT for builing up a dog's confidence and socialization skills. This may well help.
Julie Sansregret - AHT, Dog trainer
1313, rue PineRidge,
J7T 2M7 (450) 424-1469