Extracting From Archive In Idvd


I have made a movie in iDVD and have archived it as I have heard the project then becomes self contained (thinknig it was a collect for output kind of thing). The problem being is I need to get back into the iMovie side of my project to edit it and I no longer have the original iMovie footage.
Is there a way of extracting the iMovie file from the iDVD archive?