@Joonie: He is asking about something else. Also direct-boot from discs for PS3 games works only with few games, because when launched that way the games assume GAMEID BLES80608 and most don't like it. For movies/music - yes, it worked since 2011.
I'll repeat what I said earlier - you cannot mount games/load ISOs from burned discs unless there is exactly ONE game in folder format under PS3_GAME.
@W00fer: Get genps3iso_v2 (from webMAN*.zip) or from some other place and use it to create your ISOs. Your game will be in \PS3_GAME but you can add another folder in the ROOT as \MY_STUFF and it will be included in the ISO and present on the disc after you burn it.
X:\TEMP
X:\TEMP\PS3_GAME <--- here is your game
X:\TEMP\MY_STUFF <--- here is your stuff
Launch genps3iso_v2 and point it to X:\TEMP - you'll get an ISO to burn and you'll be able to play the game and have your data.