We present an architecture for developing applications which need to integrate legacy business enterprise information systems in a large distributed environment. In particular we address the problem of building virtual factories by interconnecting existing physical factories. The proposed architecture consists of several different frameworks each of them addressing a specific design problem: the communication framework, the security framework, the interface framework and the persistence framework. The communication and security frameworks give solutions to the communication problem based on mobile code and Internet technologies. The interface and persistence frameworks address the problem of the integration of the legacy IS which, in the new system, will be wrapped and presented as a standard business object. Each framework has to be customized for each virtual factory to build.