Modifies le fichier /etc/apache2/sites-enabled/owncloud
Avec:

<VirtualHost *:80>
        ServerName owncloud.damload.com
        DocumentRoot /home/dam/public_html/owncloud
        <Directory /home/dam/public_html/owncloud>
                Options FollowSymlinks
                AllowOverride all
                Order allow,deny
                Allow from all
        </Directory>

        LogLevel warn

        CustomLog "${APACHE_LOG_DIR}/owncloud.log" common
        ServerSignature Off
</VirtualHost>


Et tu /etc/init.d/apache2 restart