If you use my method of base SWF to load content SWFs, this would be done by recording content "history" in an Array so that you can go back/forward through the history stack. But since you're trying to replicate AS1/2 loadMovie() to _root I don't know - you will wipe any variables in _root when you replace with the new SWF, right? So you cannot have persisting history variable. You can pass a variable as query string I suppose. In any case what you're trying to do is not how you load external SWFs in AS3.
... View more