New Issue: Optionality of soap:headers at binding level

Folks,

I received an action from the recent WS-I meeting to communicate an 
issue identified by the BP team to this group (part of my liaison 
duties:) for potential resolution in WSDL 1.2.

In a nutshell the issue has to do with how can a WSDL mark some of the 
headers at the soap binding level to be optional. WSDL 1.1 specification 
is silent on this and it is not clear if it is an error if some of the 
headers defined in a WSDL document are missing from the SOAP message 
that is generated. WSDL 1.1 spec does not provide a way to mark 
soap:headers "optional".

Current spec for the soap:bind extensions stands as follows:

<soap:header message="qname" part="nmtoken" use="literal|encoded"
                            encodingStyle="uri-list"? namespace="uri"?>*


The WS-I BP team feels it would be desirable to provide a way (an AII?) 
to mark the soap:header elements optional or required. Alternatively all 
headers can be made mandatory unless marked optional via the newly 
defined attribute.

Thoughts?

Regards, Prasad