We trained genghis on a pad when he was really little, and he was really good at always trying to make it on the pad though just like human boys aim is initially an issue. I can't tell you how many times it landed half on half off. This quickly made up our minds to train him to go outside. That took a long time as he would only go on or near a pee pad. Even on long car rides we would put him on grass and he would just stand there clearly full of pee needing to go looking for a pee pad. We finally just started putting pee pads outside and he went imediately. DH thought this was hilarious cause we were standing in the cold for about 20 mins waiting for pee pee just staring and giving the pee pee command, and nothing. As soon as the pad came out he peed a puddle the same size as himself right in the middle of the pad. Then the looked really happy. Anyway we used pee pads outside for a few weeks which worked pretty well though there were many accidents where his pee pad was before, and there was the relapse when he got neutered, but now that he's almost one, I think he's got it down, and so have we
he uses a doggie door and gets treats when we see or know that he's peed/pooped outside. He'll do anything for treats.