Оплата WebMoney проблема с кодировкой - [VM1] Оплата и доставка

<?php
$order_number		= $db->f("order_id");
$total_sum_to_pay 	= $db->f("order_total");
$shop_uri 		= WEBMONEY_CURRENT_SITE;
$url 			= "https://merchant.webmoney.ru/lmi/payment.asp";
$payee_purse		= LMI_PAYEE_PURSE;
$payment_description= LMI_PAYMENT_DESC;

$post_variables = Array(
"LMI_PAYMENT_AMOUNT" 	=> round( $total_sum_to_pay, 2),
"LMI_PAYMENT_DESC" 		=> $payment_description,
"LMI_PAYMENT_NO" 		=> $order_number,
"LMI_PAYEE_PURSE" 		=> $payee_purse,
"LMI_SIM_MODE" 		=> "0",
"LMI_RESULT_URL" 		=> $shop_uri."administrator/components/com_virtuemart/notify_wm.php",
"LMI_SUCCESS_URL" 		=> $shop_uri."index.php?option=com_virtuemart&page=account.order_details&order_id=".$order_number."&Itemid=4",
"LMI_SUCCESS_METHOD" 	=> "2",
"LMI_FAIL_URL" 			=> $shop_uri."index.php?option=com_virtuemart&page=account.order_details&order_id=".$order_number."&Itemid=4",
"LMI_FAIL_METHOD" 		=> "2"
);

echo '<h4>Активируйте WebMoney Keeper перед переходом к странице платежа</h4><br />'; // Please remember to activate WebMoney Keeper prior to processing next step
echo '<form action="'.$url.'" method="post">';
echo '<input type="submit" value="Оплатить заказ" name="formSubmit" class="button"/>';
	
foreach( $post_variables as $name => $value )
{
echo '<input type="hidden" name="'.$name.'" value="'.htmlspecialchars($value).'" />';
}
echo '</form>';
 ?>