Everything is pretty much default.
I've tried changing each of those mentioned in different combinations, but with no change in behavior.
I just now tried copying the table under request properties, but it only gives me data from the first line.
For my basic attempts, there is no attachment, just XML. But if I don't enable/force MTOM, the content doesn't get the right header for the web service it will need to go to. I'm working with a test environment right now, so I have some flexibility, but the production environment requires MTOM or it won't answer.
Does that help?