I guess, there is no feature to generate these null tags using xmlNodeToDocument service.
However, this can be done, using the documentToXMLString service by setting generateRequiredTags to true.
And I guess, this will generate only the null fields if they are mandatory. But it won’t generate if they are optional.
and for optional fields, i believe, there won’t be any issue in Webservice invocations with this approach, as they are anyway optional fields.
so, convert the run time xmlString (won’t consists of all nodes) ->xmlNode->xmlDocument (consists of all nodes at design time, won’t present at run time ) ->xmlString (with above option, generates missing tags)
#Integration-Server-and-ESB#webMethods