post_action only when the download is completed

[tais46@googlemail.com]

i have a problem with post_action on nginx.conf.
And sorry for my bad English  :)

User come to my page an start a download.
Now i have add the post_action and add the download_end.php
in the download_end.php i will count the download stats (write into 
database).
That work very beautifully without any error.

The problem is now, when the user cancel the download
download_end.php will execute, but thats false!

Only when the download is realy completed, than i will open 
download_end.php
but NOT when the user canceled the download!

Are there any tricks?

Thank you for your help

       location /files/ {
           internal;
           alias /home/files/;
           post_action /download-stop;
       }

       location /download-stop {
           fastcgi_pass 127.0.0.1:9000;
           fastcgi_param SCRIPT_FILENAME 
/var/www/page/download_it_end.inc.php;
           fastcgi_param QUERY_STRING     file_id=$file_id; //thats ok!
           fastcgi_param   REMOTE_ADDR     $remote_addr;
       }