Missing (Delivery header- Domain) DUNS in .RNO file

We are having some problems identifying RNO sent, which is sent to TN, in the RNO customer is sending the Delivery Header with out DUNS in the following element.
("/messageReceiverIdentification/PartnerIdentification/domain/FreeFormText), according to the Rosettanet Spec’s this field is optional and that’s why they are not sending it.

We tried to update the RNO with the DUNS in it and resubmitted the RNO to TN every thing works fine.

Is there any work around for this??