Hey Shelley! Sorry about the poopie puppy problem!
Try an online search for homemade sprays made with a mixture of tobasco and other peppers. I don't know the exact quantities you would use, but you would simply mix the tobasco and pepper with water in a pressure pump sprayer and spray the whole area. Then, when poopie comes back, he'll smell the pepper and hopefully go away. If he comes into the space, the pepper oils will get on his paws, he'll lick it off, and learn to associate the smell with a little burning tongue. He'll eventually figure it out! The downside is that you'll have to be out in the heat spraying your pepper juice every few days. The good side is that this treatment is totally natural and doesn't involve harmful chemicals.
Of course, if the culprit is the Taco Bell chihuahua, this advice is null and void.
Good Luck!
Susan