What did you do when Dozer peed on a blanket? How did you discipline? He could possibly be thinking, "I don't want to get my master upset, i'll get rid of the evidence" and this isn't uncommon. I would definetly mention it to the vet. How old is your Dozer again? He may only be able to hold himself for half an hour or maybe only hour and so, I know you said this doesn't work, but I would start from the beginning again and possible get a smaller crate if the one you have now is too big. First do ever half hour, and take him outside on the leash to pee, when he does, praise and make a big deal out of it. Then an hour and keep doing that. This is not something he will just grow out of, so it's important you train him as early as possible that this is not an exceptable behavior.