I don't think I have a really helpful question on this one. All of mine were very easy to crate train especially with the pooping part. If anything, it was the peeing that they just couldn't hold. Then along came Daddy who was just A.W.F.U.L. He took ages to stop pooping in his cage - it was just so frustrating. The amount of baths he had each week ... I'm suprised he didn't shrink into a miniature buldog!!
I have nothing to give you for advice ... nothing worked with him because he didn't seem to mind being covered head to toe in his own poop. In the end it was just time that seemed to cure him of it!!