Humph, when any of my instructors see me 'duck' they tell me 'this is japanese martial arts...no ducking...enter....'
I'd like to think a palm strike (shomen ate, which has been mentioned in this thread) would do the trick...but frankly, with someone that big, I don't think I'm going 'inside'...I prefer to chip around the edges, let him lean toward me, and extend him. But hey, its all monday morning quarterbacking, so who can tell?