I plan to train my 8 week old westie to potty inside on a pad until he has his last parvo shot (Parvo really bad in my area - AL). Then we plan to transition to potting training outside. What are your recommendations as to how to transition from inside to outside? My concern is that we train him to go on the pad he is willing to please and learns fast then we change after the shot. How do we do this and not confuse him?