Hola. Como no lo he encontrado por ningún sitio, pego el contenido de un pequeño FAQ sacado de Destructoid donde explican como cambiar de cuenta.
Lo más interesante es que el redactor explica que puede utilizar los juegos japoneses con su cuenta americana... haciendo backup de contenido antes, y desactivando la cuenta anterior desde la Vita.
Fuente (con capturas de pantalla):
http://www.destructoid.com/how-to-use-ps-vita-with-more-than-one-psn-account-218688.phtmlHow to switch PSN accounts on the PS Vita:
1. Backup!Assuming that you've already set up your Vita with one PSN account, and that you're wanting to use another, you'll want to back up your game data and saves first. I was particularly nervous the first time I tried this, as I had game saves for several Vita games stored in the system.
The backup process is very easy, though. Simply connect the Vita to a PC or PS3 and use the Content Manager app. You'll need Sony's software for PC use. "Backup" is one of the four options given in this app. Select this to dump the entire contents of your memory to the connected device. You'll be able to restore this with one touch through the same app later.
If you don't need a full system backup, you can choose to simply export your game saves.
2. Restore and deactivate the PS Vita systemYou'll need to "restore" the PS Vita to sign on to the other account you want to use. This means that the data and settings will be wiped to factory standards, and that you'll have to set up the system all over again. The good news here is that this process is very quick.
Important: Note that you'll need to deactivate your Vita while logged into one PSN account to use it under another. You probably won't want to do this from a PC, as you're only given one activation every six months! Deactivating from the Vita makes it so that you can activate it again without issue. To do this you'll go to the Settings app, choose the PlayStation Network option, and then pick System Activation and follow the instructions.
-OR-Or, you could start the Vita's Restore process. The system should prompt you to deactivate the system first before restoring. It should also ask if you'd like to delete all data on the memory card. The whole process takes less than a minute.
3. Set up the Vita with your other PSN account.It's simply a matter of logging in with your other PSN account. Again, the setup process only takes a minute or two. You'll set the language, date/time, and watch the silly mandatory opening movie. Then you're good to go!
4. Reload save files and content. Content Manager makes it easy to select everything you'd want back on your Vita. Note that you won't be able to move over games that belong to another PSN account, but game saves and other data work just fine.
5. And when you want to go back to the first account, Restore.
FAQ: Does a US PSN account work on a Japanese Vita? Yes, it works. You won't be able to access the US PS Store as it's not up yet. This means that you won't be able to download your games to the system, either. Still, you can access everything else, including friends lists, trophies and messaging.
Can I use Japanese games while logged into my US PSN account? All of mine work fine!
What happens if you don't deactivate the Vita before restoring it?You may not be able to activate the system under another PSN account, as it's still tied to the previous one.
Can you load PSP games from your PS3 or PC to your Vita on a US PSN account.Not yet, it seems. I tried it from both the PC and PS3 a couple of times.
Can you just switch out memory cards, using a dedicated card for each PSN account?Our second memory card is on order, so we can't test this yet. But I see no reason why it wouldn't work. We'll report back soon on this.
