Can someone fix my pants?

We decided to dive into the world of potty training with Graeme. We introduced the potty about a year ago and have encouraged him to use it, mostly before his bath when we are conveniently located right next to it. He has complied with increasing frequency over the last year, but we are far short of having him trained. In light of his recent 3rd birthday (the magic age when boys are supposedly capable of being trained - ha, that's a funny one - training a boy to do ANYTHING) and our open calendar for the next month we decided to try in earnest this past weekend. We put Graeme into underwear, placed the potty in the living room, set the watch for 60 minute intervals and bought a big bag of m and m's. When the watch beeped we encouraged Graeme to use the potty. He received one m and m for trying, two for peeing. He quickly figured out the incentive scheme and was more than happy to comply, frequently reporting that he needed to pee-pee within seconds of completing the task. We also learned that 60 minute intervals were too long when after 45 minutes he said "can someone fix my pants?" The innocence of this question penetrates my bones. He wasn't embarrassed or upset or mad or any other emotion that might accompany making a mistake as an adult. He simply needed help because his trousers were suddenly soaked. I realize that he doesn't completely understand the "urge" to pee, but this is part of the training, I suppose. Or maybe it's still too early for him. Graeme also insists on wearing his underwear backwards. We've tried to explain that the "pocket" goes in the front, but this feature of boys underwear is really useless for a 3-year old who is still learning his way around his body parts. So, when he realized that the pocket didn't have much purpose he decided that he'd rather have the fun feature of the underwear (e.g., a picture of McQueen, Superman, or Spiderman) in front where he can see it. Hard to argue with that logic. So, my big boy is walking around with backwards underwear trying to learn the sensation of needing to urinate while staying engaged with his legos and trainset and the presence of a potty in the living room. It's a very confusing world through the eyes of a 3-year-old, indeed.