Half turn to whip position, half turn to catch
Swing out and make a half turn at the frontend. At the platform, lift your legs up in front of you, pass them through your arms and hold them straight in front of your face (away from the bar) in a whip position (although facing the opposite way from usual). When you reach the frontend again, push your legs forwards towards the bar (to unfold your body) making a half twist at the same time. This trick can also be performed with a straddle whip (legs outside of arms).
You can find out more about this trick in following books: