I've not done it, but as I understand it a fresh ham will pretty much be pulled pork since it will not have been cured or smoked if it's a green or fresh ham.
The only thing I can think that would give you trouble is that there's not as much marbled fat in the ham as there is in the shoulder. I'm not sure if this is a good or bad thing. I know that since the rendered connective tissue and fat in a butt or picnic makes for great flavor, you may notice a difference in the ham, being more lean.
BUT....this is all speculation.
Big JT's Smokin' BBQ Competition Team
"There is a freedom that cannot be taken from you. There is an inner freedom that nobody can ever deny you of, even if they lock you in a cell and block you off from the world. Seek that freedom."