The WS-A spec defines a single default value for the RelationshipType
attribute of a wsa:RelatesTo header, specifically wsa:Reply.

The spec further defines that the value of this attribute is a QName of type
anyURI.

We are considering using this attribute to contain an indicator of the type
of response message that is returned from a service where that service has
more than one possible outcome (e.g. business response, acknowledgement of
request, etc). So we MAY do something like :-

<wsa:RelatesTo RelationshipType="myNS:Ack">...</wsa:RelatesTo)

Obviously myNS: will be declared somewhere in scope.

A couple of questions :-

1. Is this legal according to the WS-A spec ?
2. Does it seem a reasonable approach (for example we could use wsa:Action
for the same purpose) ?

Cheers

Fraser.