I'd like to know the answer to this too!
I have read that if you take puppy outside as soon as it gets up in the morning and absolutely HAS to go then it will.
I have been actually thinking about a small turf filled indoor potty to get her started and then taking THAT outside. Should have seen my DH's face when I told him I was looking for a way to grow grass inside!
I'm sure interested in hearing what all those "PROS" out there think too!