webmail subdomain nginx ispconfig3

Hi,

I'm installing a new server with ispconfig3 an nginx on Debian.

With Apache it was possible to create a vhost for webmail subdomain.

So I searched a bit and found a bit code I changed to match my serversettings:
webmail.vhost in nginx sites-enabled folderL

Code:

server {
  server_name webmail.mydomain.ext;
  access_log /var/log/nginx/webmail-access.log;
  error_log /var/log/nginx/webmail-error.log;
  root /var/www/horde/;
  index index.php;
  location / {
    try_files $uri $uri/ /rampage.php?$args;
  }
  location ~ \.php {
    fastcgi_split_path_info ^(.+\.php)(/.+)$;
    fastcgi_param PATH_INFO $fastcgi_path_info;
    fastcgi_param PATH_TRANSLATED $document_root$fastcgi_path_info;
    fastcgi_param PHP_VALUE "cgi.fix_pathinfo=1";
    fastcgi_pass unix:/var/run/php5-fpm.sock;
    fastcgi_index index.php;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    include fastcgi_params;
  }
}

I pointed dns record to this and it worked.

This worked untill I added mydomain.ext as site to ispconfig3.
Now I get the "Welcome to your website!" message. So it looks like adding the site (with or without autosubdomain) changed how nginx serves the subdomain.
How to fix it so I can use this webmail subdomain?