[quote=sedilis]
1) Prepare the first part of your campaign.
2) Have your players play part one.
3) At the end of the session save the game.
4) When you want to add the next lot of content use load from the GM Mode menu rather than Prepare.
[/quote]
Tested this now and it works just fine.

Would be really nice to be able to save/export/import player characters though. I cant see anyway to permakill a player character and have them reroll a new one or have a new player join.