* @param currency 3-letter ISO-4217 currency code: USD, JPY, GBP
*/
public Document chargeOrder(String orderNumber, float amount, String currency)
throws ProtocolException {
Money money = createMoney(amount, currency);
ChargeOrderRequest chargeReq = _objectFact.createChargeOrderRequest();
chargeReq.setGoogleOrderNumber(orderNumber);
chargeReq.setAmount(money);
JAXBElement<ChargeOrderRequest> elem
= _objectFact.createChargeOrder(chargeReq);
return convertToDOM(elem);
}