This idea may sound a little crazy, but it worked for me. My son is five now, but when he was about two, (and yes boys are slower to potty training) we got a potty chart that you can download for free from several sites. We explained that he would need to fill the chart up with stickers and then we would have a..."poop party" yes that's right a poop party. My son's cousin who is the same age was going through the same thing so my sister-in-law and I decided that it would be a team effort, they both would have to complete the chart, and the chart was for a month, so it can take a little patients but it worked for both. What kid doesn't like to have a party, with that said, it doesn't have to be anything fancy, we did it with the family only. I went to Baskin Robins and got a "log roll" which is ice-cream rolled in a layer of chocalate cake, so you can image what it looked like (yes a poop log ). I was a little imbaraced to ask that I wanted it to read, "Happy Poop Party," the things we do for our kids:)
The party was a big sucess, we got a jumpy so it felt like a real party, we had a blast and a fun page in my sons scrapbook. The boys were potty-trained it worked great, the next hurdle was/is bed-wetting, geesss:) Good luck, they all evently poop and pee in the toilet...so don't stress to much.