By enabling the home button.
1.Download a copy of pergame and quickestexit.
2.Extract them both to /seplugins
3.Add pergame.prx 1 to game.txt (dont worry about quickexit)
4.Open pergame.txt,delete everything and add:
Modify the game path so it points to FileAssistant
Now when you run FileAssistant,pergame.prx will load quickexit.prx for fileassistant only.When you want to exit FileAssistant just hit the home button and it will kick you back to the xmb.