Your English is very good. The easiest way to start (I think) is to look at WWW::Mechanize, because WWW::Mechanize will already send "good" headers like a browser would. If that's not enough and you need to add other headers, WWW::Mechanize has methods for that as well, and in the emergency case, you can create your own HTTP::Headers for your HTTP::Request object that you then send through LWP or Mechanize.

I suggest you compare the headers your Perl script sends against what the Flash sends and add/change headers until the thing works.