In this paper we examine, how the benefits of Supply Chain Management, as announced by the literature and widely accepted, can simulatively be proven. We first present selected results of a survey conducted on the European automotive industry, which show an evident need for transparency, in terms of the quantification of the added-value of Supply Chain Management. For this purpose we introduce an XML-based prototype for modeling and simulating cooperative scenarios in supply chains, and illustrate its flexible architecture and the interaction between modeled scenarios and optimization routines through XML interfaces. In the context of this prototype we describe a simulation scenario in which the transportation activities in a supply chain are modeled and planned. We then run simulations in a cooperative and in a non-cooperative context and compare the results for the entire supply chain. This comparison can provide information about the benefits of cooperative logistics planning (i.e. Supply Chain Management), which for instance can be realized by implementing Supply Chain Management software for distribution planning purposes.