Ah, bark, I don't have a Mannie, unfortunately, but have long wanted one and I've read up quite a lot about the breed.
Unfortunately, I think Rusky's advice is probably pretty accurate. Maybe if he was inside you wouldn't need to have the alarm on: they are pretty determined defenders of their territory!
Hope it all works out, he looks like a lovely dog. Are you going to breed from him? There seem to be quite a few Mannies in NSW but I've never seen one in Melbourne although there is a breeder here. Can I ask which breeder you got him from?