Hot Rod is very good at peeing on the pad. He would rather poop outside or on my front door rug.
I've only ever seen him lift his leg once while on the pad, normally he squats but he for sure lifts and marks outside constantly. lol
We keep a pad inside their expen, in the sunroom when it's warm enough for them to be out there and then in hubby's garage-which they get taken out to several times throughout the night. He will poop on the pad in the garage more than in the house but only if his schedule get messed up, like it has been with all the snow we've had. Fortunately, he's pretty regular in that he goes first thing and at lunchtime when we go for a walk.
My 2 have been pad trained ever since we brought them home. I would definitely say you need to watch for any signs of them needing to go and make sure you praise and treat once they do. Use a phrase for when he is actually going so he will become familiar with it. This will get him to learn what it is that you want him to do on the pad.
I have read where others have wrapped pads around something like a 2 liter soda bottle and set it in the middle of the pad so the dog can lift his leg. I've never had to do this so I don't know if it works or not.
Good luck, it is possible!