Issue 392: revised proposal

I took an action to provide a revised resolution for issue 392. I
hope this captures all the points which were raised during this
morning's discussion. Apologies for the wording, it is a litle
rough.

Jean-Jacques.

<proposal>
Intermediary Considerations
===========================
A SOAP message can travel through zero or more SOAP
intermediaries. This sections describes the requirements posed on
SOAP intermediaries supporting this specification.

A SOAP intermediary MUST be able to access any secondary part.

A forwarding SOAP intermediary MUST in general forward every
secondary parts contained in the incoming SOAP message, except
when the specification for a SOAP header block calls for the part
to be removed or changed. An active SOAP intermediary MAY change
or remove any secondary part even in the absence of such a
mandate. It is strongly recommended that such changes be
described in a manner that allows such modifications to be
detected by affected SOAP nodes further along the message path.
[*Ednote: do we want this fine distinction? If not, we could just
delete the last two sentences.*]

A SOAP intermediary MAY insert new secondary parts.

The integrity of the URI scheme used to reference secondary parts
MUST be maintained accross SOAP intermediaries.
</proposal>