I have three dogs and have successfully integrated two new babies in to the house. I also train dogs and have fostered many rescue dogs. I agree with the prior poster, socialize your dog and if possible give him something to smell.
When you first come home with the baby, go in and greet Braveheart first, let him get his joy out of his system. Bring in another blanket from the baby. Let him sniff it and absorb it. Then bring in the baby. Let Braveheart sniff him/her from head to toe as long as the baby is ok with it. This will let Braveheart assuage his curiosity.
I suggest a good obedience class before you get the baby. Even if Braveheart is well-trained, a reminder course will do you both good. He will need to be able to sit or leave a room when directed. He should not be jumping and if he is accustomed to sleeping on the bed, he should understand that he needs to get off when told, without complaint.
Another advantage of an obedience class is that it will give him some mommy and me time. Even after the baby comes, continue to spend some personal time with him. He does need to know that even if his place in the pack has shifted, he is not being rejected.
Unless your baby is terrified of dogs or Braveheart really responds badly in the beginning, do not separate them. Let him understand that your new baby is a pack member and one that he needs to respect an care for.
Also remember that a crawling baby looks very odd to a dog. He may growl because he does not know what the baby is trying to do or supposed to be. If you had your baby from infancy, it might not matter as much. As your baby may come to you crawling, it is more of an issue.
As much respect as Braveheart needs to learn, so does your baby. Be sure that Braveheart has a safe place to go to, his bed, his crate, something. If Braveheart growls do not correct him, change the situation, send him to he his bed. My reason is this. A growl is a warning. If you take a growl away from him, his only option is to bite. Do not cosset him, but just quietly and firmly separate him and the baby and tell him to go to his bed.
The go to your bed, crate, what have you should be a command that you are training now.
Best of luck with your soon to be bigger family. Reassure Braveheart it is all good - the baby will soon be throwing food from his/her high chair.
One last thing NEVER EVER leave your new baby and Braveheart alone unsupservised.
Peace
N.