How to lay out my folders so an SSI "include" command can be executed?

Q: My SSI script is not bringing up the correct file...only the [an error occurred while processing this directive] message.  Is it possible for me to use the command  <!--#include virtual="\global\header.asp"         --> and have this site work properly (even if I have to rearrange/rename my folders)?   Yes, it would be easier to change the SSI command, but here's why I can't:

I am a web designer for the Coast Guard, and am creating a "mirror site" for my clients to approve their pages before the site goes live on the www.uscg.mil domain.   I would like to set up my site so that my clients can approve their site, and then log in via FTP and 'copy-paste' their pages into their uscg.mil FTP folder to put them live.   The    <!--#include virtual="\global\header.asp"         --> is how the SSI must look for it to work properly in the www.uscg.mil domain...so I'll do whatever tweaking is necessary to get this to work in my http://uscg.cutteragent.com/ domain as well.    Just need a direction on how to do that!   I'm comfortable creating .htaccess code if that's necessary.   THANKS in advance!