Swing out and turn around at the front end. Over the platform, bring your feet up in front of you and place the front of your feet against the bar. You can either bend your legs or keep them straight (you may find you can achieve more rotation with bent legs).Before you reach the peak at the front end 'break' from your folded position and sweep your legs back behind you until they are above your head and your body has risen over the bar. Make a half turn and turn your hands on the bar.
You can find out more about this trick in my books:
Thanks to Theo and Jean Francois for providing a video for this page.