I presume you mean unhooked blind as you talk about the bar being ripped out of your hand...
If you're landing fine, with your board pointing downwind/toward the kite it sounds like you've got the hardest part nailed
Ok, a few questions...
What kite are you using? How powered are you when you're trying this?
Is your arm being pulled straight by the kite and at an awkward angle for you to hold on?
Most freestyle kites land with the kite pretty slack, but if you start edging against the kite before you pass the bar, that slack will go very soon, and you wont be able to hold onto the bar, especially as you're in a very awkward position.
my top tips:
1) hold on with the bar in both hands until your body rotation forces you to release your back hand; keeping the bar in closer, and hopefully you'll have a bit of time to pass the bar before your arm gets pulled straight.
2) Try to twist your arm around and bend it into the small of your back. This is much more comfortable, and easy to pass the bar from. It will take a bit of practice to do this, as a lot is happening at once.
3) If you don't have a C-style kite, try one.
4) Try it with a very flat, efficient board - you'll be able to plane and pop with much less kite power and get the technique right.
Hope this helps