In addition to the other comments - looking at LWP::Simple I don't see a post() subroutine in that module. So unless that is defined elsewhere in the code that you aren't showing you'll have to build something that gets the POST arguments from the browser and resends them to the real URL.

I tend to use LWP::UserAgent for this, like so:

my $ua = new LWP::UserAgent;
my $req = new HTTP::Request POST => "http://$url";
$req->content_type('application/x-www-form-urlencoded');
$req->content("param=data to send to the client");  # note - should be
+ URL encoded
my $res = $ua->request($req);
   
# Check the outcome of the response
if ($res->is_success) {
    return $res->content;
} else {
    return $res->error_as_HTML;
}
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