The Sims 2 Castaway: How To Fast Forward

It's not impossible to fast forward the game 
Left Trigger + Dpad: UP


To return the speed to normal
Left Trigger + Dpad: Down


To pause the game
Left Trigger + Dpad: Down(when you not fast forwarding)


To resume the game
Left Trigger + Dpad: Up


Actually it's similar to how you switch the sims 
Left Trigger + Dpad: Left or Right(depend on which sims you want to switch to)