this is how i would do it:

use CGI;        
use CGI::Session;
$cgi = new CGI; 
$session = new CGI::Session("driver:File", undef, {Directory=>"/tmp"})
+;
$cookie = $cgi->cookie(CGISESSID => $session->id);
print $cgi->header( -cookie=>$cookie );
[download]

ciao
knoebi