And although it has changed.... Microsoft have made statements in other forums that there are 2 KB's on the subject describing how it could be done. It is no longer done via a webservice, and that it is now performed via supplied command line interface. They also went on to say, that although they dont / wont support 3rd part / external epg providers - they will supply the required information to those who need it.
So I would hope the dialogue is open - and it is not far away, considering all their offers of help