DECLARE @ItemMessage XML 
SET @ItemMessage=cast(N'<?xml version="1.0" encoding="utf-16"?>
<A>
  <B id="32dcd7ee-530b-4551-8946-071934753476" value="5">
    <C>1</C>
  </B>
  <B id="C7A9D074-4C82-4192-8AFB-DE89CE00E4FD" value="2">
    <C>2</C>
  </B>
</A>' as xml)

SELECT T.c.value('@id','uniqueidentifier') as id, 
T.c.value('@value','decimal(12,5)') as value,
T.c.value('(C/text())[1]','int') as c
FROM @ItemMessage.nodes('A/B') AS T(c)