R2 and L2 functionality mapped to the Vita's rear touch pad.
Remote Play on PS Vita just got a whole let better with the release of patches which make the God of War Collection, ICO HD and Shadow of the Colossus HD compatible with the service.
God of War Collection features the HD versions of God of War and God of War II.
You'll need a copy of either of these games on PS3 – patched with the new update - and a WiFi connection for your Vita in order to access Remote Play.
Sony has even taken care of remapping R2 and L2 DualShock 3 buttons to the rear touch pad on the Vita.