I may be completely misunderstanding what you want, but here is something you might look at. I was using it to test eccomerce transactions. Change the url's to fit your needs.

#!/usr/bin/perl
use warnings;
use CGI 'cgi';
use LWP::UserAgent;

# from a config file
our ($secure_server_address,$cgi_directory);

print "Content-type: text/html\n\n";

#my $test= 'FALSE';
my $test= 'TRUE';
my $relay;
my $cgi = new CGI;
my %input= $cgi->Vars();
foreach $name (keys %input){
        $value = $input{$name};
        $relay .= "$name=$value&";
         }
$relay .= "Ecom_transaction_complete=$test&";
$relay .= "IOC_response_code=0&";

open (RT,">test/respgen.test");
print RT $relay;
close RT;

my $ua = LWP::UserAgent->new();

my $req = HTTP::Request->new (POST => "$secure_server_address$cgi_dire
+ctory/boacc.pl");
$req->content_type('application/x-www-form-urlencoded');
$req->content("$relay");
my $res = $ua->request($req);
print $res->as_string;
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