You are going to have to remove the outer ring. It has two pin hole locations, it has LH threading. Campagnolo made a tool for this, but not the easiest nor the most difficult to find. With that removed from your description the top section of the bolt will fall out. Now you have some choices, use a puller, as found at an auto parts store or Sears, or buy a Campagnolo tool as found on ebay for C Record cranks which were also "one key" release.