PerlAccessHandler for POST access

do you know for my this simple PerlAccessHandler, why HTTP GET works, 
but POST doesn't?

use strict;
use Apache2::RequestRec ();
use Apache2::RequestIO ();
use Apache2::Connection ();
use APR::Table ();
use Apache2::Const -compile => qw(OK FORBIDDEN);
use Apache2::Request;
use Digest::MD5 qw(md5_hex);


sub handler {

     my $r = shift;
     my $req = Apache2::Request->new($r);
     my $ts = $req->param("timestamp");
     my $key = $req->param("authkey");
     my $digest = md5_hex($ts);

     return $key eq $digest ? Apache2::Const::OK : 
Apache2::Const::FORBIDDEN;
}


1;


Thanks.