So we started potty training with DS (2.5) last saturday. We've only had two wee accidents all week, so that is going well and we've been out and about etc. He has even been dry all night for the last two nights 
BUT - he won't even try to poo on the potty, saying that he wants to do it in his nappy. So then I offer to put a nappy on him and he says no, and stops trying to poo. So eventually he ends up doing it in his pants. We've only recently got over a withholding problem after a poo-in-the-bath incident (another story!) so I don't want to make an issue of it, but how do I get him to poo on the potty??? or at the very least, in a nappy...