Thank you for reply! I have not noticed that. And it could have been a good way to go if only
P.S. All that would have been easier if only I could change the CGI application, but I can't.

And it has a handler on
$q=new CGI;$q->param('user');

Still if nothing else is possible, I guess the application should be changed, and that is an other headache and not for me.