[users@httpd] files directive inside a directory directive

[oximoron]

Hello,

I use the <Files> directive in order to ask a Ldap authentication on a 
file.

If I use the .htaccess file for that authentication, it works perfectly.
If I put the <Files> directive inside the <directory> directive in my 
apache conf (/etc/apache2/sites-enabled/https), when I go on my webpage, 
I have a:

"Authorization Required
This server could not verify that you are authorized to access the 
document requested. Either you supplied the wrong credentials (e.g., bad 
password), or your browser doesn't understand how to supply the 
credentials required."

But no popup shows up in order to ask me those credentials.

In FF, if I push F5, nothing changes.
In Iron (chrome like browser), if I push the F5 key, the popup shows up, 
I can give my credentials and it then works well.

Here is my conf:

Alias /jyraphe /var/www/jyraphe/pub
<Directory /var/www/jyraphe/pub>
        AllowOverride None
        Order deny,allow
        php_admin_value open_basedir 
/var/www/jyraphe/pub/:/var/www/jyraphe/documents/var/:/usr/share/php/:/tmp/

        Allow from 192.168.1.0/24

        SSLRequire %{SSL_CIPHER_USEKEYSIZE} >= 128

<Files index.php>
             AuthLDAPURL 
ldap://localhost/ou=Users,dc=xxx,dc=yyy?uid?sub?(objectClass=*)
             AuthType Basic
             AuthName "'Serveur XXX'"
             AuthBasicAuthoritative Off
             AuthBasicProvider ldap

             require valid-user
</Files>
</Directory>

I strangely, found nothing on the web about such a problem.
I must not have find the right words to search with, I guess..

Where can the problem come from?

Thanks
Kenny