Thanks for your help I appreciate. Unfortunately this is something I have already tried. The result is that it doesn't show any more the referer at all.
Another way that doesn't show a referrer at all is using a JavaScript redirect.
I have also tried with the .htaccess file.
Then I tried with perl two different ways.
Honestly I give up I am sure this is simply impossible. For sure is it possible to do a frame redirect or a proxy to access the content but this is not what I want.
I'll be very surprise if someone is able to find a solution for this.