Do you have the pad laying out on the floor. I found that the pups will end up on the edge of a pad if you just place the pad on the floor. The thing that works best for me is putting a large litter box on the floor and then lining the box with a pad. That way the pad can't move around to much and the pet is forced to get into the box to use the pad. Which pretty much makes it impossible to poop or pee out of the box. It also contains anything that might seep under an edge.
Hope this helps.
PS Any container that has a lower edge will work for this. Once on a vacation I used the bottom of a cardboard box.
