You really have to have a front punch and a standing back tuck to do this pass. When you land your back handspring you have to have a really high rebound and shift your weight ever-so-slightly towards the front (instead of the back like you would for a back tuck). Then just tuck your body exactly like you would for a front punch. Once you land your front tuck, the back tuck is pretty much a standing back tuck because you lose so much momentum after the front tuck. You will get a little rebound from the front tuck, but it won't be enough to get you rotated over for the back tuck on it's own. It's really more of a standing tuck. If you are looking to do a similar pass that is a little easier, I would recommend doing a roundoff back handspring back tuck to a front tuck, because you won't lose momentum between skills. Good luck, hope this helps!
You have to be able to do everything you said before you attempt to do it. After that, trying it all on a tumble track helps then slowly work your way to the actual floor. It takes a lot of practice. Good luck!