I believe its not mandatory segment for TN recognizion,but this is required segment for VAN providers…Actually it just indicates about the delimeters contained in the edifact document.
I have submitted documents with out UNA before UNB it worked fine…Please try submitting with EDI submiter of the WmEDI adming webpage.
It depends on what exactly you’re doing. If you’re submitting the doc to TN for outbound batching, then you probably don’t want TN to do its recognition and (optionally) transaction splits. What you can do then is to construct the bizDoc yourself (createBizDocEnvelope, addContentPart) and persist or route the bizDoc to TN.