Ok- if you are sure the crate is the right sized, then is he pooping just at a certain time of day? (mornings- evening...) Could you adjust his feeding times so that he has eliminated before he gets put in the crate?
Do you know what type of situation he came from before you had him? Was he caged all the time so he had no choice but to poo in the crate? If so, it's going to be a harder thing to retrain, but it can be done. There is some good information in the library on rehoming puppy mill dogs and potty training them.
Also- as an FYI, rawhides are really bad for small dogs (all dogs, really). They can break off and swallow pieces that later swell and cause intestinal blockages.
Oh, and I forgot to say welcome to YT!
