not sure if i can help, my son will be 3 in may but he will not poo in the toilet. initially he didn't want to wee either. We started him with a sticker chart every time he did a wee on the toilet he got a sticker & a fruit tingle. He knows that when he starts pooing on there he will get trains from the thomas set + also offered 2 fruit tingles when he goes but he wont! To the business of going out, maybe you can reward (bribe) him with something small if he will wear his pullups, that would be a start. Does he wet himself because you dont get him to the toilets in time or because he just cant be bothered letting you know? I used to put the timer on the oven for 3o minutes to remind me to ask him to go, when we went out i put the pullups on but would take him to the toilet as soon as we get to the shops or wherever. he kept weeing in the pullups at home so i just "bit the bullet" and put the undies on & have only had about 5 accidents! good luck!!
mum of 3 boys aged 11, 13 and 14