I found a video that shows exactly the kind of problem I have with backside 360's:
Backside 360 Snowboarding at Revelstoke, BC, Canada - YouTube
So yes, he pulled it, but look at how leaned back he is at about 270 and how tail heavy he lands. This rotation axis is all weird. This is what happens everytime and i usually land straight on my ass at 270 on the landing. I see a lot of people doing the same thing too.
Are you supposed to really try to lean into landing while rotating? I can land 180's and i have to think about this when doing it. At the same time though, i've been looking at videos of people sticking 360's and it seems like they can be very off axis at the 180 mark, but somehow twist it all around in the end. Like the one in this video:
Snowboarding How To Backside 360 a jump with Kimmy Fasani - TransWorld SNOWboarding - YouTube
Actually, the one in this video seems to make a lot more sense in terms of getting the axis right (im gonna work on this one):
snowboard backside 360 - YouTube
But it seems like either way, people have figuired out how to get it around.