I think you should call your doc right now! Just to check in, and see if he/she wants to see your child.
No milk, for diarrhea. Even if he wants it! Stick to the BRAT diet: bananas, rice, applesauce, and toast (or other starches, like crackers or plain noodles). Soy milk is ok too, unless it makes his diarrhea worse.
My son hates pedialyte too, but he got very dehydrated from a stomach bug a couple of months ago. We got him to eat the pedialyte frozen pops, and to drink the apple "singles." (He liked the singles, because he could hold them and drink them on his own, rather than needing a sippy cup. He felt like a big boy!)
I also gave my son jello, at my doctor's advice. Some docs worry about the sugar making diarrhea worse, but for a while there it was the only liquid he'd take!
Good luck, and call your doc!