The development of inter-organizational systems requires a well defined development process. UN/CEFACT’s Modeling Methodology (UMM) provides such a development process. We served as the editing team of the UMM 1.0 foundation module, which is defined as a UML profile. First experiences of applying UMM in real world projects have disclosed some limitations. Accordingly, we propose integrating new concepts into a new version 2.0 of UMM. In this paper, we show the adapted UMM development process, which is demonstrated by means of a waste management example.