IBM Integeration BUS: Trace Node - ibm-mq

Question

In simple message flow in which there are 3 nodes. One is MQ input node which is receiving an xml input. Other is MQ Output node which is receiving msg passed from MQ input. In between there is trace node. The trace node is configured to generate trace in a file. it trace down the whole xml msg, its content in the file. What if I want to track a single tag of xml file like contact number.
i.e:
<contactDetails>
<contactName>Acme</contactName>
<contactNumber>09200209</contactNumber>
</contactDetails>
Which pattern should I use? I have tried ${Body.contactDetails.contactNumber} and ${Environment.contactDetails.contactNumber} but I am getting null in output. Can anyone help?
EDIT: Below is the whole message:
<?xml version="1.0" encoding="utf-8"?>
<tns:In_Request xmlns:tns="http://www.ibm.lab.com" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<ActionRequest>O</ActionRequest>
<DateRequest>10/12/2005</DateRequest>
<customerNumber>1</customerNumber>
<customerName>ACME Hardware</customerName>
<customerDetails>
<customerAddress1>1254 Main St</customerAddress1>
<customerAddress2>Suite 12</customerAddress2>
<customerCity>Dime Box</customerCity>
<customerState>TX</customerState>
<customerCountry>USA</customerCountry>
<customerPostalCode>76543</customerPostalCode>
<customerCreditLimit>1200</customerCreditLimit>
<customerCreditScore>123</customerCreditScore>
</customerDetails>
<contactDetails>
<contactFirstName>Freddy</contactFirstName>
<contactLastName>Bloggs</contactLastName>
<contactPhoneNumber>555-123-6543</contactPhoneNumber>
</contactDetails>
<requestDecision>Y</requestDecision>
<comments>Just a Comment</comments>
</tns:In_Request>

Answer 1

I see the problem now.
Body in the reference points to the root element for the domain in which your message is parsed, e.g. to Root.XMLNSC if you set the message domain to XMLNSC on the input node of your message, so not to the root element of your message.
If you want to trace the value of the element contactPhoneNumber from the example message, you should use the following reference:
${Body.*:In_Request.contactDetails.contactPhoneNumber}
So after the Body, you must specify the whole path to your element. The *: part is needed because the root element in your message is in a namespace.