 If you don't suspect a physical ailment behind the behaviour then...
It's not enough to just crate him. You have to make sure he goes to the bathroom (both if you feel he should have to do both) and THEN put him in the crate. Get a feel for how often he needs to go and take him out at those times. No food and no water should be in the crate w/ him. Those are only given at supervised times and then he must go outside before and actually "go" before you put him back in his crate.
Other than that, it sounds like you're on the right track.
Now, if he's going right after he's already gone outside, that's a different matter. PM me if that's the case.
~Leslie |