php提交表单有关问题

php提交表单问题
公司搞了一个第三方网银支付代码,妈B原来以为是网银,原来是网付通,那边只给JAVA和了一段C#代码的接口代码,这个要怎样写提交表单到这代码运行?自已搞PHP的,不太会C#,求高手改一下。。。

private void button1_Click(object sender, EventArgs e)
        {
            //签名
            string SendCertFile = "C:\\Documents and Settings\\29897\\桌面\\代收付系统接口\\代收付测试\\代收付测试\\TESTUSER.pfx";        //发送方证书主题(商户证书)
            string SendCertPassword = "123456";                             //发送方证书密码
            GneteCrypt obj;
            obj = new GneteCrypt();
            String strSign;
            //DateTime dt = System.DateTime.Now;
            //string OrderNo = dt.ToString("yyyyMMddHHmmss");
            //String strSignMsg = "";
            String strPlain = "<?xml version=\"1.0\" encoding=\"GBK\"?><GZELINK><INFO><TRX_CODE>100001</TRX_CODE>" +
                "<VERSION>04</VERSION>" +
                "<DATA_TYPE>2</DATA_TYPE>" +
                "<LEVEL>0</LEVEL>" +
                "<USER_NAME>YSCS002</USER_NAME>" +
                "<USER_PASS>111111</USER_PASS>" +
                "<REQ_SN>20110125001</REQ_SN>" +
                "##strSigMsg</INFO>" +
                "<BODY>" +
                "<TRANS_SUM>" +
                "<BUSINESS_CODE>00600</BUSINESS_CODE>" +
                "<MERCHANT_ID>000000000000351</MERCHANT_ID>" +
                "<SUBMIT_TIME>20110125082020</SUBMIT_TIME>" +
                "<TOTAL_ITEM>1</TOTAL_ITEM>" +
                "<TOTAL_SUM>1</TOTAL_SUM>" +
                "</TRANS_SUM>" +
                "<TRANS_DETAILS>" +
                "<TRANS_DETAIL>" +
                "<SN>0001</SN>"+
                "<E_USER_CODE/>"+
                "<BANK_CODE>105</BANK_CODE>"+
                "<ACCOUNT_TYPE>00</ACCOUNT_TYPE>"+
                "<ACCOUNT_NO>60138270140042110021</ACCOUNT_NO>"+
                "<ACCOUNT_NAME>张三</ACCOUNT_NAME>"+
                "<PROVINCE>广东</PROVINCE>"+
                "<CITY>广州</CITY>"+
                "<BANK_NAME>建行</BANK_NAME>"+
                "<ACCOUNT_PROP>0</ACCOUNT_PROP>"+
                "<AMOUNT>1</AMOUNT>"+
                "<CURRENCY>CNY</CURRENCY>"+
                "<PROTOCOL/>"+