Ok I modified the httpd.conf a little but I am still having no luck seeing the header X-Remote_User using fiddler , ngrep or wireshark leading me to believe that it is infact not getting written to the header If you can have a look and let me know what you think does the configuration below look correct?
<Location /SASLogon/login> AuthType CAS Require valid-user RewriteEngine On RewriteCond %{LA-U:REMOTE_USER} (.+) RewriteRule . - [E=RU:%1] RequestHeader set X-Remote-User %{RU}e env=RU </Location>