Proxy authentication

[Petr Hracek <phracek2@xxxxxxxxx>]

Dear apache users,

I have a pretty problem.
On my system (Apache 2.2.3) I have configured following proxy:

<VirtualHost 
_default_:443>
SSLEngine on
DocumentRoot 
"/opt/apache/htdocs/ssldocs"
ProxyPass       /PAC/   http://192.168.187.101:8080/PACCBAdmin

ProxyPassReverse    /PAC/       http://192.168.187.150:8080/PACCBAdmin/

RewriteEngine
 on
RewriteCond %{REQUEST_METHOD} ^TRACE
RewriteRule .* - [F]
RewriteMap unity txt:/opt/apache/conf/unity.map
RewriteRule ^/([^/]+)$              ${unity:$1|/$1} [L]
RewriteRule 
^/([^/]+)/(.*)  ${unity:$1|/opt/apache/htdocs/

ssldocs/$1}/$2 [L]
RewriteLog "/var/log/apache2/rewrite_log"
RewriteLogLevel 3

<IfModule mod_authz_host.c>
    <Directory />
        Options +Indexes +Multiviews
        AuthType MSEC
        require valid-user
        satisfy Any
    </Directory>
</IfModule>

<Location "/PAC/">
    ProxyPassReverseCookiePath /PACCBAdmin /PAC
    AuthType  MSEC
   require valid-user
</Location>

</VirtualHost>

I would like to do something like:
when user add to the URL following http://<ip_address>/PAC/
then first of all they should enter username/password authorization and afterwards proxy page should be opened.
Authorization is done over AuthType MSEC.
Authentication is OK, but afterwards I have receive HTTP 404.

On the system I have my own module which takes care about authentication process. This works fine.
But afterwards I receive HTTP 404.

Could you please help me with that issue.

Thank you in advance

-- 
Best Regards / S pozdravem
Petr Hracek