Apparently people are toilet training their dogs too! Here’s an excerpt from Step 2:
“Take a plastic tub or wee wee pad, at least two inches deep, and put it in your dog’s “out” spot. When you take Fido out, continue using the code word and get him used to peeing and pooping near the tub or pad, Then, even if you ease him in, one paw per-day, get him to pee and poop while standing in the plastic tub or wee wee pad. You’re going to have to give it a rinse out, and I’d suggest using dish soap and water to keep it clean while you’re going through this process. Going to the bathroom in a tub or wee wee pad is not a natural feeling for your dog, so give him/her lots of love, praise and encouragement while it figures it out. Princess probably thinks you’re crazy, but she loves you, so she’ll follow your lead eventually. When she gets into the tray to do her business without flinching, you’re ready to move on.”
Do It And How 