I realised that last week I only sent the XML outline of how a ZNG
request/response may look. Attached is the WSDL from which this is derived
as well as a sample XML SOAP/URL envelopes it defines.
This is somewhat different from Pouls XML Schema mainly so that it can bind
to different transports such as HTTP easily. Also I don't include an
explicit version element as the XML namespace for the schema.
I think it also addresses the issues Ralph mentioned and also doesn't suffer
from ASN.1 anachronisms (such as a root Request/Response element) as well as
avoiding xsd:choice which isn't implemented well at present.
I've also included both SOAP and URL bindings in the WSDl.