Ok, so I re-read your question and have an answer for you. I think what you are trying to say is that you have Ensemble, not HSF, and you still want to be able to send documents (XDS provide and Register).
I did some testing with the Open Source Integration mirth and stumbled across an example channel of theirs, and it is doing a provide and register with straight up SOAP calls to the end point.
Basically, build the required soap envelope accordingly, then send a PDF or document to the repository using MTOM.
This is what makes HealthShare its money, encapsulating all that manual construction of objects that need to be sent to endpoints.
Anyway, a screenshot of the Mirth channel destination make give you an understanding:
http://www.integrationrequired.com/wp-content/uploads/2013/02/Capture.PNG