"parameter XI.InterfaceNamespace missing"

Using a WSDL generated using the 'Define Web Service' tool in Integration Directory, I've attempted to post to the outbound interface defined as a Web Service. The SOAP adapter returns a java error indicating I'm missing the parameter XI.InterfaceNamespace. I assume the errors refers to a parameter that is supposed to be in the <soap:address location="..."> attribute.

Could anyone please elaborate as to what this error means?

Thanks,

--jtb