From what I can see on the web, the developer account only allows access to test. What was the error you're getting back?
I'd say if the test environment works with that plugin, then the real one should as well, there must be some other setup issue.
Thanks for replying.
I have uploaded a document using their 'manual' process, so unlikely to be an issue with the developer account.
I agree on your suggestion that if it works with a test function thenthe reals ones should too!
The response from their support team was
The one thing I noticed is you do not have any namespaces enabled. This is what our system looks for and uses to translate the XML code.
Presumeably the test functions would need the namespaces too?