T.
I don't know what is is about the poop that scares them. Shortly before my sond's 3rd bday, I started trying to get him to poop in the potty. He told me he would do it when he was 3. He would pee if I put him on but would not always tell me when he had to go. Shortly after his 3rd bday his preschool went on fall break. I decided that we would stay home for the week and potty train. I threw alway the pull-ups completely and put him in underwear with vinyl training pants over them. He had accidents Sat-Monday(both poop and pee). On Tuesday, no poop at all. On Wednesday we had to return library books that were due. I was terrified he would have an accident but he didn't. When we got home, he pooped in the potty for the first time. After that, we didn't have any problems. He was completely trained within a week.
A few things to note:
1. When he had an accident, he had to clean it up (even the poop). He had to help dump the poop in the potty so he could see how yucky it was
2. When he went poop he got a lollipop (a special treat for him) and a sticker on a chart. When he got the sticker chart filled (10 stickers) he got to pick out any toy he wanted at the toy store.
3. Be prepared to stay home all week. Have some new toys/games/videos on hand to keep the kids entertained.
4. With both my kids (i have a dgt too) the key was getting rid of the pull-ups.
Good luck!