In Information Technology, but also in Ontology engineering, a strict distinction is made between metadata and data, or, in Object Oriented terms, between classes and instances. This paper presents a mechanism to maintain metadata in a decentralized way, in order to flexibilize open electronic business. By defining instances assets, data models can be manipulated in operational systems, together with those instances. Using the UN/Cefact Core Components Technical Specification as a framework, decentralized developed metadata becomes negotiable. The presented mechanism removes bottlenecks of the scalability of open B2B systems.