ActionScript 3.0 :: Create A Preloader That Forces A Reload From The Server, And Not The Cache

I need to create a preloader that forces a reload of the Main.swf from the server, and not from the user's cache.

This is because the site (for a big music festival) will get frequent updates, and users will visit more than once.

I have my HTML-metatags set up like this:

HTML Code:
<META HTTP-EQUIV="CACHE-CONTROL" CONTENT="NO-CACHE">
<meta http-equiv="Expires" content ="0" />
<meta http-equiv="Pragma" content ="no-cache" />

...but these get kind of, uhm, ignored?

So now I'm looking for a solution in my AS3 preloader. I've tried this trick, that works fine with xml-files, but with swf's it doesn't seem to work:

PHP Code:

l.load(new URLRequest("Main.swf"  + new Date().getTime()));