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.