I am trying to see if anyone has found a way to take a knife using tominage(sacrifice throw). My problem is that the distance is to short and i can't get the leg to his stomach to pop uke over. If anyone has figured this out or knows how to please let me know. I am very good with this throw but i just can't get this one. Please any advice will help thanks.

Why would you want to? Now if you are 'playing' with the knife and just want to do it for fun, thats one thing. But to stand in front of someone with a knife in hand, and drop to your back is suicidal. Even if the person doesn't know anything about how to use a knife he may lose his balance and accidentaly cut or stab you. Second of all if he knows how to use a knife, he will cut you to threads. Disarm the man, get the knife away then do your fancy throw. You do know the origin of that throw was to get a soldier of his horse, not to use it against weapons, formal or otherwise

I have no desire to use this against someone with a real knife just playing.