Any way to keep SWFs from storing data in C:/blahblah?

I'm using FFP and installed flash ('self-contained' on my usb stick) successfully, it's running good. Except that I still can't figure out how to keep flash interactive games from storing data in a C:\... path. I'd really prefer if the games would store their data wherever I tell them, or at least off the firefoxportable\ branch. Is this a behaviour I can force on flash apps under FFP?