I really don't have any advice for you, but my pup does the same thing!
I started potty training him outside, and he'll poop/pee outside. He first started pooping out in my living room on the carpet, so I just started watching him when I'd let him out there and when I'd catch him, I'd pick him up say 'No, bad boy' and take him outside and say 'Outside'. Don't know if it's working, but lately he'll scratch on my door when he wants to go outside. And amazingly, he'll poop outside! Since he's seemingly getting the hang of it, we've only had one accident, and it was my fault. I didn't take him outside, and I hopped in the shower. When I got out, he had pooped right next to his pee pad! LOL. Of course, I couldn't take him outside then because he wouldn't know what he did.
He pees on his pee pad MOST of the time, but sometimes I'll catch him peeing AROUND it, which is close enough. LOL.
But anyways, maybe someone else will have better advice on how to get him to actually poop on the pad, because I am no expert.
