defining a reason code

Hi,

I have another question regarding extending response codes.

I defined the following response message:

<epp xmlns="urn:ietf:params:xml:ns:epp-1.0" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:schemaLocation="urn:ietf:params:xml:ns:epp-1.0 epp-1.0.xsd">
  <response>
    <result code="2200">
      <msg>Authentication error</msg>
      <value>
        *<reason>5004</reason>*
      </value>
    </result>
    <trID>
      <clTRID>FCCN-12386</clTRID>
      <svTRID>TRN7063050306</svTRID>
    </trID>
  </response>
</epp>

where the reason element represents the code to a specific verified problem.

But I don't know if this is valid XML.

Can I define this this way, or I must include something with the 
namespace? like

    <result code="2200">
      <msg>Authentication error</msg>
      <value>
*        <ptdomain:panData 
xmlns:ptdomain="urn:ietf:params:xml:ns:ptdomain-1.0" 
xsi:schemaLocation="urn:ietf:params:xml:ns:ptdomain1.0 ptdomain-1.0.xsd">
      **    <ptdomain:reason>**5004**</ptdomain:reason>
**        <brdomain:panData>*
      </value>
    </result>

Thanks for your feedback.