With deeper levels of external process integration and a growing number of elec-tro¬nic business relationships, enterprises strive for becoming more inter¬operable with their business partners. Although B2B standards are supposed to ensure scal-able B2B integration and m:n connectivity, enterprises face the challenge of am-biguous interpretations of standards when it comes to their implementation. This paper develops a conceptual model for service-based B2B interoperability which leverages web service technologies for implementing industry standards. The au-thors instantiate the conceptual mo¬del in a concrete B2B scenario in the automo-tive industry where a consortium of automotive manufacturers and suppliers are current¬ly redesigning their inter-organizational Engineering change Manage¬ment (ECM) processes. From the evaluation, they conclude that it is not sufficient to specify that standards are used related to pragmatics, semantics and syntax. In order to ensure interoperability, additional design rules are needed which define how industry standards are mapped to a web service design.