Remap hotkey for PS Vita screenshots

[HeyItsLollie]

One of the more awkward-to-use features of the PS Vita / PSTV is taking screenshots: Home + Start. This is made even more awkward for PSP games via Adrenaline, where pressing Home opens up the "Do you want to exit this game?" menu - so you have to press Home once, then Home+Start.

I'd like to be able to remap the default screenshot hotkey combo, so that I can set up something simpler/less awkward. eg: the touchpad button on a DualShock 4 controller.