ponygirl
Thats what happened, initially, with me too. I had to start all over again.
Please ditch those god awful pull-ups, I can't help but think it may be confusing him. Pants one minute and pull-ups the next. Be strong hang-on in there. Keep reminding him that there will be no more nappies/pull-ups, make a big thing of it get him to help throw them in the bin, when out and about point out children in nappies saying 'oh look theres a baby, hes got a nappy, you dont have a nappy, you're not a baby are you? you're a big boy now you've got pants', lots of praise etc etc Subtly making him aware all the time.....
Good luck, you can both do it!
loon xx