implementing airplane help--a few questions

We are attempting to implement "airplane help" with our application, so that when our users have an internet connection, they'll get a live help file (webhelp) that we have sitting on a server, and when they're not connected to the internet, they'll get a local version of the help file (.chm file) that we deliver to them with our application.

In RH's online help, it says to "Ask your technical writer which window(s) to call." I guess I was assuming these "windows to call" would have a file extension on them, but as far as i can tell, they don't...they just have a name and that's it...no extension. So...with regard to the .chm file, I suppose we just use the name we designate as the "Default Window" when we generate a chm file? Ours is called "main" (we don't use any customized windows or skins for the .chm file). For our webhelp file, we use the skin called XP Blue; so I assume that's the window we should call for Webhelp?

Just wondering how other people who are using "Airplane Help" deal with different versions of your Help file. I assume you must keep multiple versions of your help file on a server so that each level of software you distribute to your end-users can call the right help file? Our situation is even more complex than just needing multiple versions of one help file to correspond with the various software levels that our end users are on...we also have multiple help files (i.e. one for retail stores, another for automotive parts distributors, etc.).

Lastly, are there any “best practices” for implementing Airplane Help? e.g., what if there is a delay in figuring out that we’re not able to get to remote help, is there a way to force the "local" help file?

Thanks much,
Laura