$response = $browser->post( $url,
   [
     formkey1 => value1, 
     formkey2 => value2, 
     ...
   ],
   headerkey1 => value1, 
   headerkey2 => value2, 
 );

my $url="http://forum.web-hack.ru/index.php?act=Login&CODE=01"
 $res = $ua->post( $url,
   [
     "refer"            =>  "", 
     "UserName"   =>  "$login2", 
     "PassWord "  =>  "$password",
     "Cookiedate" => "1"
   ],
    "Cookie"         => "Твоя печенька",  );