Operation potty training

This is going to be a rough week. I started the morning off with the scale up and the bank account low. Plus, I am committing myself to knuckling down and having potty training boot camp. Jacob is potty trained. Jonah and Jackson are not. Okay, so this is the thing. When the boys are naked they never have any accidents. They poop and pee in the toilet all day long. However, when I put a diaper, pull up or even underwear on them they just go in their pants. So, today and the rest of the week we are inside with naked boys running around. I don't know what else to do. I have told the boys they will have to earn their pants. And surprise, surprise... they have both pooped and peed in the toilet all day long. So, my question is when do I give them pants? Any ideas??