[Mediawiki-l] External Authentication that uses company URL

[Jim]

I'm trying to setup external authentication with MediaWiki.  I've gone over 
http://wiki.case.edu/CaseWiki:External_Authentication time and time again 
but it's not exactly clear.

Here's how our company authentication for web access works.

- I check to see if a cookie exists.  If so, decrypt it and get user info.
- If cookie doesn't exist, redirect to the company authentication URL.  In 
that redirect, I specify a "return to" URL so after the user authenticates, 
it knows where to send the user back to.
- Go back to first step.  Since the cookie should now exist, I have user 
info.

I figured I would use mod_rewrite in .htaccess to redirect 
index.php?title=Special:UserLogin to say index2.php.  index2.php would get 
the cookie and be the return point for the redirection if needed.  But now 
that index2.php has the user info, I need it to login, creating the userid 
if needed, to mediawiki.  This is where I'm totally lost.  Any help would be 
greatly appreciated!