This trick is very similar to a Reverse Gienger, but with an extra half twist so that the flyer ends up facing the platform (as they started)
Swing out and turn around so you are swinging facing the platform. Similar to a Reverse Back Somersault, set slightly after the platform, beat just before the poles and the sweep your legs forward. Let go of the bar and somersault backwards with a full twist to catch the bar again.
Rather than a full twist, it is easier to think of this trick as a Reverse Gienger where you catch the bar in a crossed grip so that the last half twist happens partly after you have caught the bar again.
Thanks to Alexis and Jean-Francois for providing this video.