How can I capture the body of a SOAP response using the order management extension?

I used this code here but it is not working yet:

import oracle.apps.scm.doo.common.extensions.ValidationException;

import oracle.apps.scm.doo.common.extensions.Message;

String accountId = header.getAttribute("BillToCustomerIdentifier");

String sourceTransactionIdentifier = header.getAttribute("SourceTransactionIdentifier");

String sourceTransactionSystem = header.getAttribute("SourceTransactionSystem");

String currencyCode = header.getAttribute("TransactionalCurrencyCode")

List<Message> messages = new ArrayList<Message>();

def serviceInvoker = context.getServiceInvoker();

def varMessage = "";

def totals = header.getAttribute("OrderTotals");

String totalAmount;

while (totals.hasNext()) {

    def total = totals.next();

    totalAmount = total.getAttribute("TotalAmount");

}

String payload =

                  "<cred:CreditCheckRequest xmlns:cred=\"http://www.creditCorpCheck.com\">" +

                                "<HOLD_CODE>HOLD_FOR_CREDIT_CHECK</HOLD_CODE>" +

                                "<SourceTransactionIdentifier>"+ sourceTransactionIdentifier +"</SourceTransactionIdentifier>" +

                                "<SourceTransactionSystem>"+ sourceTransactionSystem +"</SourceTransactionSystem>" +