[horde] Using http authentication

[Michael Wisniewski]

Hi!

I have apache setup to authenticate users using mod_authnz_external.  
Basically, this fills a variable $_SERVER[REMOTE_USER] with the 
authenticated username.

I attempted to follow the wiki page and add this to .htaccess

RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization},L]

However, I am not using cgi and probably won't in the future.  Being 
that PHP assigns the $_SERVER variable with the login name, how can I 
get Horde to recognize this and not prompt for the login.php page?

Thanks!