How can I recreate the Montgomery Inn "Cincinnati style" barbeque sauce at home? I love Montgomery Inn barbeque sauce for its tangy/vinegar-y flavor, however it's often not in stock at the stores in my area.

Does anyone know how I could achieve a similar flavor with a homemade sauce?
Found this...

http://www.copykatchat.com/sauces/7118.htm

I've never been there, so I can't judge; but might be a good place to start.