Ever though about maybe using a litter box? They make doggie versions but you can use a cat litter box, a box is pretty much a box. They make special dog litter too if you desire. I use feline pine personaly. I find with some puppies going in the box keeps them from "walking off the pad". In other words it keeps them in one area. You don't even have to use litter really, litter is nice but a puppy pad works fine too. It should be pretty easy since he already knows he supposed to "go" on the pad.
One warning though, I have had puppies that learn the use the litter box well enough but they tend to sort of hang their little butts over the side of the box and poo... Usualy mens we need a bigger box and most of them figure it out quickly enough and stop doing that.
I have to say using the litter boxes has made life easier with larger litters of pups and when it rains and they won't go outside as adults they will usualy go back to the litter box if you provide it for them. Nice
One warning though, I have had puppies that learn the use the litter box well enough but they tend to sort of hang their little butts over the side of the box and poo... Usualy mens we need a bigger box and most of them figure it out quickly enough and stop doing that.
I have to say using the litter boxes has made life easier with larger litters of pups and when it rains and they won't go outside as adults they will usualy go back to the litter box if you provide it for them. Nice