A kicking-chain might be a good idea. You might not be able to control the emotion he has - but you can control the action. A kicking chain (like this one: http://www.doversaddlery.com/product.asp?pn=X1-0403
) is a good investment in this type of situation (for roughly $30). The kicking chain attaches to the hing pastern, and prevents the horse from striking out (at the wall, door, etc.)
They are very safe, very humane, and effective. I've seen them used several times, and within a week, sometimes the chain is no longer needed. The message has gotten across to the horse that he can't kick, and that's that.
Best of luck!