Warner Bros. Pictures own the rights to the motion picture "Creepshow" in the U.S., and Universal Pictures own the rights to the film in the United Kingdom. Universal decided to do a CREEPSHOW Special Edition when offered the chance, including the documentary. This is why it is exclusive to the U.K. and not available elsewhere.
To American fans' disappointment, Warner Bros. have stated repeatedly (and reportedly to director George Romero's face), that they are not interested in licensing a special editon of the film for the U.S.