C.B.
Hello! We had the same problem with our son. He was trained to pee in the potty for at least a year before he would poop. We knew he was able to control his bowels, because he would sit on the potty for 20 mins without going and then immediatley get up and go in his pants. Here are a few things we tried: small toy for each success (matchbox car in our case), sticker chart (with a large treat at the end), and snack of choice, PRESCHOOL and the you must use the potty rule (he had one accident there and got pretty upset about it). Truthfully though, the only thing that finally worked was we left him alone :).
Good Luck!!!
C.