UN/CEFACT's Modeling Methodology (UMM) is a well accepted and formal notation to analyze and design B2B business processes. In a service oriented architecture (SOA) environment process specification languages like the Business Process Specification Schema (BPSS) are used to configure B2B information systems. However, mappings from UMM models to BPSS process specifications currently exist just on a conceptual level. This results in a gap between defined B2B processes and BPSS configurable e-commerce systems. Thus, a model driven code generation of BPSS descriptions is required. In this paper we present a technical implementation of a transformation engine that generates BPSS process specifications from a UMM model represented in the XML Metadata Interchange (XMI) language. This implementation bridges the gap mentioned above. It has been used in the EU project GILDAnet to generate BPSS descriptions from logistic processes modeled in UMM.