*nods* I remeber being in the very same boat with mine. ESPECIALLY when school was about to start for him, and he still refused to use the poddy! O.o

But then the unexpected happened that just MIGHT work for you. I didn't plan this, it just happened by accident and I was totally shocked that it worked.

My friend showed up at my house unexpectedly with her daughter who was my son's same age. They were already friends and played together at times. At the time, my son was on the poddy and refused to go on it ((again -.- )) BUT, when he heard his friend was there, and SHE encouraged him from the other side of the door... It took some time... like 30 minutes or more ((IF I remember correctly since it was quite a few years ago)) but.... VOILA!! He went!!

Never had a struggle after that! Just lots and lots of victory dancing!

Maybe a "friend", or someone outside of the family that your child REALLY loves spending time with could help in the same way.

I seriously hope this idea will help you... if not, post again! I have some autism parents that may know another trick or two and I can check with them for you as well!! *hugs of support*