Uh. Double fronts are difficult, I know this. But dude, you gotta jump up ^ and high, and then flip like a bitch. Maybe even throw it slightly off axis to whip your body around (you may end up spinning a 180 with it, but it'll help you not land flat on your back)
Keep on working on it, you'll have it.
I have stuff of double fronts on here. But I'm not about to post any new footage of trampolean unless its something original.