The Internet-of-Things (IoT) has long become reality and contributes to the digital transformation of many industrial domains. IoT technologies are at the core of industry 4.0 application scenarios, contribute to cyber-physical system implementation, smart connected products and new business models exploiting their potential. There is plenty of work on how to specify, design and implement IoT solutions, but a lot of enterprises struggle to create business value from IoT technology because they have difficulties to define the organizational integration. Methodologies for model-driven engineering (MDE) of IoT solutions should encompass both, organizational and system development and integration, but existing model-based approaches focus on the technical perspective. The paper proposes a modeling approach integrated into enterprise modeling techniques to compensate for this lack. The enterprise modeling language 4EM is extended by adding a method component for IoT modeling. The main contributions of this paper are (a) a summary of the state-of-research in the field, (b) an industrial case for model-based IoT development, and (c) a meta-model and tool support for IoT modelling.