Swing out and back to the platform. Instead of a normal set ('seven' position), lift your legs in front of you and hold them at 90 degrees. Swing down into the centre and as you reach the poles (centre of the swing) beat back as hard as you can with your legs. As you move up towards the peak at the frontend your legs will follow behind you and then move in front and up to the sky. Hold your body straight and let go at the peak, look back over your head to catch. This technique is the basis for all back somersault tricks.
You can find out more about this trick in my books:
Thanks to Fly'n Fit Trapeze School in Japan and Pneumatic Arts @pneumaticarts for providing videos for this page.
IMAGE CREDIT: Thanks to Emerald City Trapeze Arts. Flyer is Laura Scoop. Thanks to David Treadwell for the photo.