Transformation into a vampire of any stripe seems to be pretty permanent. I mean, Harry searched for years for a way to turn Red Court vamps back to human, and if memory serves he found one thing that might have worked. Black Courts are even more transformed than Reds, so I can only imagine that it'd be even harder than that.
We're basically talking direct action by the heaviest of the heavy hitters. This would be Archangels, one of the Faerie Mothers, or maybe an ancient and powerful god. Big, big mojo, in other words.