J.D.
My daughter had this problem also. She was potty trained for #1 at age 2 and never had an accident. She was in daycare and never went #2 there. She would save that for home. She'd come home, put on a pull up, make in it, and then I would help her take it off and clean up. I guess I shud have enforced that she clean up alone, but I just didn't have the comfort level to cleaning up a big mess while she learned. I tried many things, games, offering a reward, nothing worked. This went on while she was 4, and dare I say, close to 5. I asked her why she doesn't do poopy in the potty and she said because she was scared of the "poop snakes". If I saw another parent buying large size pull-ups I would ask their advice. When I tried not allowing the pullups in the house she just held it in and would cry and get terrible cramps. I cudn't do that to her and gave her back her pull ups. One time, on her own, she made a poop in the potty, before she was 5. I was so happy, I don't know why she did it, but after that, it was never an issue again. When I was going thru this, one friend told me, "Don't worry, she won't go to college in diapers" and she was right.
good luck
J.