Describing an application as a simple composition of services allows advanced features that exploit different platforms to be conceived and to be formalized at a high abstraction level. Several languages and formalisms have been proposed to this aim; UML diagrams are also used to this purpose. Starting from such an abstract description, still much work is needed to derive a working application, with a model-driven development process that needs to introduce and formalize many details. In this paper we report an experience in deriving an executable formal model from a high level specifications, originally given following a mainly architectural UML approach. The development process is illustrated on an automotive case study. A state of the art code generation tool is then applied to produce a prototype implementation of the analyzed system.