If you include the "httpd.conf" which is created by ispman.ldap2apache, you will have virtualhosts only. If you point your browser to an IP only, Apache will deliver the content of the 1st virtualhost in that list. To get influence about the "default" host, I recommend to create the following snippet as "/opt/ispman/templates/vhost.conf.header" and set this path in "configure->apache->vhost header" in web UI. It will simply add it as 1st occurrance of a virtualhost for that IP and thus make it the default, redirecting IP-based requests and non-added host with that your IP to /var/www/default. You can create a index.html in there or whatever.
<VirtualHost ####INSERT YOUR IP HERE, * DOESN'T WORK> ServerAdmin webmaster@localhost DocumentRoot /var/www/default <Directory /var/www/default> Options -Indexes FollowSymLinks MultiViews AllowOverride None Order allow,deny allow from all #RedirectMatch ^/$ /your/redirect/path/ </Directory> ErrorLog /var/log/apache2/error.log </VirtualHost>