I\'ve got a hosted WCF service that I created a custom factory for, so that this would work with multiple host headers:
///
/// Required for
I don't think this necessarily has anything to do with your factory.
See
http://msdn.microsoft.com/en-us/library/system.servicemodel.channels.transportbindingelement.manualaddressing.aspx
or others among the first few Bing hits for "manualaddressing". It sounds like the binding being used is incompatible with some other portion of the stack/messaging logic.