The PS3 doesn't have the hardware built in to communicate the video feed to a handheld. It's not something that would be unlockable with a simple firmware update - it's literally impossible for the PS3 and PSV to function like that.
It's POSSIBLE it could be done with a USB add-on, but that introduces lag and another purchase, and isn't even confirmed as possible. It's not just simple wireless. It would need a dedicated wireless connection specifically for each device.
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