Soaking a BP right before shed is most likely going to make the shed go bad. Soaking a BP not only stresses BP's out, but also removes oils that are necessary for the shedding cycle.
Obviously your vet isn't as knowledgable as he/se sounded.
You should stop soaking your BP... all you need to do to get good sheds is make sure that the cage humidity is at 60% or higher.