From a Whip facing the platform, full twist back to hanging under the bar.
Swing out from the platform, turn around at the front and get into a Whip position at the platform end. Once you arrive back at the front end, push your body straight and let go one hand. Make a full twist (the hand on the bar won't need to move) and grab the bar with the second hand. This move is seldom seen on flying trapeze and is 'borrowed' from the discipline of parallel bars.
You can find out more about this trick in following books: