Originally posted by Scooby4
Everytime he would roll over I would PROMPTLY turn him over to his feet. I would NOT pet him while exposing his belly ONLY on the head/back. I did have to physically grap his tail and head flip him onto his feet. It did not hurt him and would have to repeat the process a few times. Each time I would tell him "No petting belly" or something like that.
hm.. I wouldn't ever do this. it sounds pretty mean, and like it would further freak out a submissive dog.

Building confidence, ignoring submissiveness, and praising will probably work very well though. Taking him to Obedience classes should help a lot! Later in his life, Agility, Flyball, competitive Obedience, or Frisbee would also give him a lot of confidence by giving him a "job". I wouldn't expect him to be a big "guard dog", but what exactly do you mean by guard dog? Is he outside or in the house? Do you want him to guard property or just alarm bark when some one aproaches the house?