[Solved] Sub-directory multi-site within a subdomain multi-site instance

I'm attempting to create sub-directory sites within a virtual host on a Fedora 11 system, so I have something like this in my httpd.conf:

<VirtualHost *:80>
    DocumentRoot /usr/share/drupal
    ServerName demo.example.com
</VirtualHost>

If I create a directory demo.example.com in the sites directory and populate it with settings.php and a files directory then I can create a drupal instance without any trouble.

If I create directory demo.example.com.site1 and populate that with settings and files then the install will start when I use the url:

http://demo.example.com/site1

But it cannot detect the settings.php file (which I have removed from demo.example.com, in fact initially I didn't even have demo.example.com there at all just demo.example.com.site1 and that didn't work either).

I have tried creating a symlink to demo.example.com.site1 and placing it in demo.example.com as site1 and also creating a symlink of directory site1 in demo.example.com and placing it in sites as demo.example.com.site1 without any success.

Any suggestions?

SOLUTION: Thanks to Damien Tournoud: http://drupal.org/user/22211

The Alias statement in the VirtualHost definition is all that seems to be required.

<VirtualHost *:80>
    DocumentRoot /usr/share/drupal
    ServerName demo.example.com
    Alias /subdir /usr/share/drupal
</VirtualHost>