Dave, Ray confirmed that the statement in my last post is correct. He did mention that you can rename your current config folder to Configuration_ASP (or whatever you want), install eCart 5 and other extensions you want to run to get a new set of config files. Then whenever you want to run eCart 4, rename the new config folder to Configuration_PHP (or whatever you want) and rename Configuration_ASP to Configuration.
I think you probably know extension architecture well enough to know what I am talking about with that brief description, but if that is unclear, I can give exact steps.
It would mainly be a pain to install the extensions a 2nd time - or keep up with dot releases in both places, but once you are installed, just renaming the 2 config folders and re-starting Dreamweaver isn't that big of a deal.
Sorry I don't have an easier method to recommend at this time.
