Шифрование Xml в SQL server

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Here is my XML column in XMLTable.

<xml_summary>
  <csrtn>3018653900
  <ordernumber>T9NE56008
  <duedate>Feb 24 2016 11:30PM
<//XML_Summary>

I would like to convert this row like below to Encrypt data in Dev to test the application with fake values. It is okay to loose the Actual value as this is for testing Env only.

<xml_summary>
  <csrtn>CSRTN_Test_Value
  <ordernumber>OrderNumber_Test_Value
  <duedate>Due_Date_Test_Value


What I have tried:

I have tried several things but not working as I am not good at XML updates

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