I think there's a little more to it. My experience when dealing with operators (partly when involved with Martin Dawes, who make billing systems, partly during my present gig) is that they see the billing platform as a core corporate item to be jealously guarded. Their network they also see the same way. To open up is contrary to their very nature; I just had to fill in a huge involved security questionnaire to start the process of linking a WAP site to an operator's systems. Giving up control of something *that key* to Microsoft... I can't see it sitting well with them.