Velocity now runs on PS Vita in the US, but you still need to use the PS3 to transfer to PS Vita.
Here’s how, courtesy of @sdhardcoregamer:
Make sure you have the install bubble on ur ps3, not just the installed game. If you dont have the bubble, redownload the game on ur ps3 first. Then plug ur vita in and use the content manager to transfer psp apps and select velocity.