I had addressed that topic/question (on a different thread) a little while back. Seeing that Tango, you, me, and a host of others are in the Houston/Rehab area, it might do us all some good to meet up again.
I had seen Tango's original post, but overlooked that someone had indeed done it with good results
Might be the answer. Even if you used a smooth finish on the ext. and Hydro on the interior. May not even need to cover the ceiling.