I have a Flat File schema that is reading a data file and then I am mapping it to a destination schema which is body part of an envelop schema. The envelop schema has a field messageID in the header and I would like to populate that field with a unique GUID. I have read it is possible to do that using property demotion but I have not had success so far. In the send pipeline I have set document and envelop schemas properly but the envelop schema does not show any value for the messageID field. Any ideas /advice?
Thanks in advance.