Thanks Jason.
I got an error message
[ERRORMESSAGE] => Error: XML not formated correctly to eWAY standards. Reason:Whitespace is not allowed at this location.
Error Code:-1072896749(Test CVN Gateway)
I'm guessing the problem is whitespace somewhere in the XML, does this message give any indication of where to look?
I've studied the whole XML request and cannot see anything wrong, and no whitespace that isnt necessary.