Hey that's a great tactic, I use it pretty often to. I use usually just fake one low kick to the legs then sort of jump forward and come down on him over his guard with punches. It's been pretty effective.
Member of DaJoGen MMA school under Dave Hagen and Team Chaos fight team under Denver Mangiyatan and Chris Toquero, ran out of Zanshin Martial Arts in Salem Oregon: http://www.zanshinarts.org/Home.aspx,