SOAP XML Request for EWS Managed API to send a attachment along with email message.

Hi,

I could send an email and save its copy in sent items folder using  XML  Soap for SendAndSaveCopy.  Its XML Soap degails are given under " Creating and sending email messages by using the EWS Managed API"  subject. 

But I need to send an text file available on my desktop (c:\desktop\SampleFile.txt) along with the email .   I couldn't find its XML Soap  request. 

I tried with the following XML given below ( sample xml is available at topic "CreateAttachment Operation").   I am deleting the URL part, because I couldn't submit this request with URLs

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi=""
               xmlns:xsd=""
               xmlns:soap=""
               xmlns:t="">
<soap:Body>
  <CreateAttachment xmlns=""
                    xmlns:t="">
    <ParentItemId Id="AAAfAENhYWdJb" ChangeKey="CQAAABYA"/>
    <Attachments>
      <t:FileAttachment>
        <t:Name>C:\Users\Desktop\SampleAttachment3.txt</t:Name>
        <t:Content>SampleAttachment</t:Content>
      </t:FileAttachment>
    </Attachments>
  </CreateAttachment>
</soap:Body>
</soap:Envelope>

It is attaching a junk file to the existing email  which is available in my inbox (existing email Item id = AAAfAENhYWdJb = ParentItemId in xml input ) .   It is not taking file from my desktop and attaching to the email. 

Can anyone help me with that to check with SOAP UI.

Thank you.