我已经在网上搜索了可能的解决方案，最终决定亲自向你们寻求帮助。
我正在设置并行支付，商家可以使用不同的货币。在我的示例中，应该支持两种货币：美元和 PHP（菲律宾比索）。这是我的请求参数：
--------------------------------------------------
[METHOD] => SetExpressCheckout
[VERSION] => 98.0
[USER] => ******************
[PWD] => *******************
[SIGNATURE] => *********************************************
[RETURNURL] => http://somewhere.com
[CANCELURL] => http://somewhere.com
[PAYMENTREQUEST_0_AMT] => 1319.64
[PAYMENTREQUEST_0_ITEMAMT] => 1319.64
[PAYMENTREQUEST_0_CURRENCYCODE] => PHP
[PAYMENTREQUEST_0_SELLERPAYPALACCOUNTID] => kyledomingo@gmail.com
[PAYMENTREQUEST_0_PAYMENTREQUESTID] => CHANGETHISREQUESTID-0
[PAYMENTREQUEST_0_PAYMENTACTION] => Order
[PAYMENTREQUEST_1_AMT] => 28
[PAYMENTREQUEST_1_ITEMAMT] => 28
[PAYMENTREQUEST_1_CURRENCYCODE] => USD
[PAYMENTREQUEST_1_SELLERPAYPALACCOUNTID] => kyledomingo@gmail.com
[PAYMENTREQUEST_1_PAYMENTREQUESTID] => CHANGETHISREQUESTID-1
[PAYMENTREQUEST_1_PAYMENTACTION] => Order
--------------------------------------------------
如果您注意到，第一个付款请求是 PHP，而第二个是美元。从语义上讲，这看起来不错，但是当我尝试调用 SetExpressCheckout 时，它会抛出一个错误10444 - The transaction currency specified must be the same as previously specified。
--------------------------------------------------
[TIMESTAMP] => 2013-05-23T02:21:35Z
[CORRELATIONID] => 81e18fe68af6a
[ACK] => Failure
[VERSION] => 98.0
[BUILD] => 6020375
[L_ERRORCODE0] => 10444
[L_SHORTMESSAGE0] => Invalid Data
[L_LONGMESSAGE0] => The transaction currency specified must be the same as previously specified.
[L_SEVERITYCODE0] => Error
--------------------------------------------------
任何指示如何使这项工作？我已经浏览了很多论坛，包括 x.com 和 stackoverflow，但似乎没有什么可以引导任何地方。
Paypal Parallel Payment with Multiple Currencies也有类似的问题，但仍未得到解答。
任何帮助都是极好的。谢谢！