It is very important to validate functional requirements and evaluate non-functional requirements in earlier design phase of a Service Oriented Architecture (SOA) by executable modeling methodology. To make SOA executable, basically, most of the proposed approaches can be divided into two categories: formalism-based ones and modeldriven ones, which both have the advantages and limitations. In this paper, we take advantage of both formalismbased and model-driven methodologies to specify a unified model-driven design and validation approach to SOA. This approach bridges generic service design and universal simulation paradigm with formal bases and practical implementation. To achieve this goal, we first extend the DEVS modeling language (DEVSML) to support nondeterministic state transition and enhance its capability to describe complex behavior of systems. Then we provide an automated transformation process using Extended DEVSML as a model transformation intermediary to bring together Model Driven Service Engineering (MDSE) with Service oriented architecture Modeling Language (SoaML) and Modeling & Simulation (M&S) methodology based on Discrete Event System Specification (DEVS). To demonstrate the applicability of this approach, we introduce an aircraft docking process in an airport scenario as the case study.