the value for the SOAP header; this can be a CFML XML value.
The mustUnderstand attribute indicates whether processing of the header is optional or mandatory. This basically translates to the node trying to find an appropriate handler that matches the header and proceed with processing the message in a manner consistent with its specification. If it can't find an appropriate handler it must return an error and stop further processing. If mustUnderstand is set to true the node is not allowed to ignore it.
Examples sample code invoking the addSOAPRequestHeader function