A case study has been published describing the e-invoicing infrastructure used for public e-procurement in Denmark. The current system uses ebXML Messaging to transport OIOXML UBL documents.

Transport of the eInvoices is based on an ebMS (ebXML Message Service) enveloping mechanism built on SOAP (ISO 15000-2). This means that the addressing information, mainly the EAN number, is part of the ebMS header. In contrast to a first solution, where there was no specific envelope format and the VANS providers had to retrieve the EAN location number from within each message, this highly improved the reliability of the system. I.e. messages are now securely sent in an electronic envelop containing the electronic address of the addressee (EAN location number) and in addition, receipts of positive or negative acknowledgements.