http://www.gamespot.com/forums/topic/29333638/psasbr-cross-buy-how-do?msg_id=339075294#339075294 To make a long story short, when I try to open disk benifits on my Ps3 to redeem my Vita version, I get an error. What do?
I'm not 100% sure but from what I understand there's multiple ways to do get the Vita version. When you're at the XMB, there'll be an option to boot PSASBR or another disc option. If you use the other option, you should be able to redeem it for download on the Vita on the PS Store.
Here's the original topic I found this info from if you need more info: