Yeah, there's that shutter cocking key, which I've never seen. And maybe that's what's described in the manual rather than the stratagem I described above (which I think is a lot easier). But on further thinking, I'd like to believe that if you independently fooled the camera into thinking there's film in it by means of the trick I described, you should then be able to fire the shutter and as a separate step, pull out each Polaroid or Fuji film shot after tripping the shutter. But I've never examined one of these instant film backs to know how they're constructed -- does the back swing open like the stock back, for instance.