Nginx, alias, php-fpm = File not Found

I'm trying to set up nginx with DAViCal.
However, I'm getting a "File not Found" with a "FastCGI sent in stderr: "Primary script unknown" in the log.
Looks like something is wrong with my aliasing but I sure can't figure it out.

My virtual host:

server {
listen   80; ## listen for ipv4; this line is default and implied
listen   [::]:80 default_server ipv6only=on; ## listen for ipv6

root /var/www-data;
index index.html index.htm index.shtml index.php;

# Make site accessible from http://localhost/
server_name just.a.server;

location / {
    # First attempt to serve request as file, then
    # as directory, then fall back to displaying a 404.
    try_files $uri $uri/ /index.html;
    ssi on;
    # Uncomment to enable naxsi on this location
    # include /etc/nginx/naxsi.rules
}
location ~ \.php$ {
    #try_files  $uri =404;
    include /etc/nginx/fastcgi_params;
    fastcgi_split_path_info ^(.+\.php)(/.+)$;
    fastcgi_pass unix:/var/run/php5-fpm.sock;
    fastcgi_index index.php;
}

location /kalender {
    alias  /usr/share/davical/htdocs;
}

}

My fastcgi_params

fastcgi_param   QUERY_STRING        $query_string;
fastcgi_param   REQUEST_METHOD      $request_method;
fastcgi_param   CONTENT_TYPE        $content_type;
fastcgi_param   CONTENT_LENGTH      $content_length;

fastcgi_param   SCRIPT_FILENAME     $request_filename;
fastcgi_param   SCRIPT_NAME     $fastcgi_script_name;
fastcgi_param   REQUEST_URI     $request_uri;
fastcgi_param   DOCUMENT_URI        $document_uri;
fastcgi_param   DOCUMENT_ROOT       $document_root;
fastcgi_param   SERVER_PROTOCOL     $server_protocol;

fastcgi_param   GATEWAY_INTERFACE   CGI/1.1;
fastcgi_param   SERVER_SOFTWARE     nginx/$nginx_version;

fastcgi_param   REMOTE_ADDR     $remote_addr;
fastcgi_param   REMOTE_PORT     $remote_port;
fastcgi_param   SERVER_ADDR     $server_addr;
fastcgi_param   SERVER_PORT     $server_port;
fastcgi_param   SERVER_NAME     $server_name;

fastcgi_param   HTTPS           $https;

# PHP only, required if PHP was built with --enable-force-cgi-redirect
fastcgi_param   REDIRECT_STATUS     200;

Looking forward to your replies.