Stubborn steer

My sister has a steer that she has worked with since October. He started out well and we even took him to a winter show. However, as the steer has gotten bigger he's gotten more stubborn. He is a puppy when tied up and in the chute, but when you try to walk him he lowers his head and runs or just won't walk. Any advice?

Lead him behind another calf.  So often these steers do this because they have no idea what they are supposed to be doing or where they are supposed to be going.  We can actually get some fairly nervous cattle shown by simply not being the first one in the ring. 

Good luck,and hang in there!