RE: [ebxml-msg] Fw: Please post (msg-header-2_0.xsd)

I agree with Arvola's reading here,
but I don't think the text is badly ambiguous.
Whether you have "perMessage or "always" for
DuplicateElimination, the sending MSH needs
to include the DuplicateElimination element,
and that is what the text says. The additional
words do help to clarify the situation, though,
and I think they would be helpful to implementers.