[alaskayorkie]

I'm still brainstorming here, so take my advice with a grain of salt.

But I would train him to go on the pee pad outside first. Take a disposable pad with you on a walk. Put it down near a tree or somewhere that you think he'll go. If he does it, treat, treat, treat.

Do that a couple times, then take him to a pee pad in the house.