pub.soap.handler:getHeaderBlock

messageContext	Object Message context containing the SOAP message from which to retrieve a header block. A message context contains properties for the SOAP message and provides access to the SOAP message. Integration Server creates the message context and passes it to the header handler. All handlers invoked by a given instance of a SOAP request or SOAP response use the same message context, which enables you to use the message context to pass information among handlers.
documentType	String Fully qualified name of the IS document type that specifies the structure to apply to the content of the header block. Specify a document type that Integration Server created while creating the consumer or the WSDL first provider web service descriptor or one that was created using the pub.soap.handler:generateDocumentTypesFromWSDL service. Integration Server uses the QName of the first field of the document type to determine which header block to retrieve from the SOAP message.
validate	String Optional. Flag that indicates whether you want the service to validate the document returned in the outputHeaderBlock/headerDocument parameter against the IS document type specified in the documentType input parameter. Set validate to: true to validate outputHeaderBlock/headerDocument. If the validation fails, an exception is thrown. false to skip validating outputHeaderBlock/headerDocument. This is the default.

outputHeaderBlock	Document List Content of the requested header block(s) as IData. This service returns multiple header blocks if the QName of the first field of the document type matches multiple header blocks in the SOAP message.
	Key	Description
	mustUnderstand	String Flag indicating whether the mustUnderstand attribute is present in the retrieved header block. A value of: true indicates that the header block contained mustUnderstand="true". false indicates that the mustUnderstand attribute was absent from the header block or mustUnderstand="false".
	role	String For a SOAP 1.1 message, specifies the value of the actor attribute. For a SOAP 1.2 message, specifies the value of the role attribute. The role parameter is not returned if the actor attribute is absent from a SOAP 1.1 message or if the role attribute is absent from a SOAP 1.2 message.
	headerDocument	Document Contents of the header block. The IS document type specified for the documentType input parameter determines structure of headerDocument

If the QName of the very first field in the IS document type specified for documentType matches a QName of a header block in the SOAP message but the content of the header block does not match the fields in the IS document type, then the retrieved headerDocument fails validation with the error