I DON'T Think So!!

I've known that potty-training my youngest is going to be difficult but this afternoon he made a comment that really worries me. "Mommy you can wipe me for the next 10 years."....NOT!!!.....Along with being able to dress himself, my son also knows how to put on a pull-up and open the sides to take it off. I don't want to rush him to do anything he's not ready to do but I'm almost certain he knows when he has to go , he's just too stubborn (I have no idea where he gets that from :)) to go to the bathroom instead of in his pants. I know he has a bowel movement every other day and so I'm quick to find him anytime he all of a sudden "disappears" upstairs. Rather than going to the toilet to have a bowel movement Liam goes upstairs and does it and if I come up looking for him he tells me to go away. Once he's done, he comes back downstairs and stinks up the place until someone catches him and changes him. HELP!! How do I get him to go to the toilet rather than hiding....He is so ready for school in the fall except that this will not be tolerated and much to his chagrin, I'm definitely not wiping him for the next 10 years, in fact I hope it's not even one more year. Any suggestions as to what to do? Do I just leave him and hope he grows out of this stubborn streak? What? I was so spoiled with my first child, he was only in pull-ups two weeks and then potty-trained, my daughter was around 3 years old but Liam.....