I shall answer this one myself, or at least let you know what I ended up doing.
For the dialogs whose next and back buttons could have different previous/next dialogs (routes), I add a new control event for the back/next buttons. I use the following:
Event = Display a specific dialog
Argument = <The dialog that I want to transition to>
Condition = <a condition which is true to redirect to that dialog>
I add a few of these events per button, so I cover all different routes where the back/next button could take me. There's some work involved and a bit error prone. Preferable one would want a stack based approach to the dialogs, so the installer itself would know how to get back to the previously shown dialog. Anyway, it worked out in the end.
For one my dialogs I couldn't change the argument. It was grayed out. Neither could I remove it. Not sure this is a bug or intentional. Thankfully the AIP-project file is editable (good job Caphyon), so as a workaround I could just delete that argument and had it gone.
Regards
Jan
