If you think about it, the skill is esentially a handspring front. Even closer, it is a handspring front vault.
You can practice the shoot to stand much like you would an uphill (or straddle up, or hecht up, or toe on/off.. whatever you want to call it).
Basically, put a porta-pit (firm), or a stack of 8" mats in front of the low bar, with enough room for the gymnast to do a sole circle (a little extra room shouldnt hurt). The height should be about the height of the gymnast's chest height at first, then add mats as they become more aggressive and show flight.
From there, do a sole circle shoot out, to stand on the mat(s). The goal is height, with the chest open and arms up (stand in a tight arch, basically). From there, do stand to jump forward roll - stand jump front (even if it lands on their back). After that, take it over a pit or in a spotting belt.
The way I learned it was similar to ryantroop...same drills but instead of landing on your feet shoot your does up and then land on your stomach.
Another great drill is doing back drop right to front tuck on the trampoline (feet dont touch the tramp in between the skills). It works on getting your toes up and then the important snap you need to do the front tuck part.
The skill itself if easier to learn from handstand or giant as well.