I am going to be watching this thread closely. My DS is 2 1/2 and has been wee trained for almost 4 months, but 'holds on' till the night time nappy to do a poo. On the days when he can't hold on he goes into another room and secretly does it in his undies.
I have been very positive with him, even still telling him it's ok and next time he can try and go on the toilet like a big boy, treats if he even tries, reward system but nothing is working!
It is nice to know that there are more of them out there!