Service-oriented integration typically combines top-down development with bottom-up reverse engineering. Top-down development starts from requirements and ends with implementation. Bottom-up reverse engineering starts from available components and data sources. Often, the integrating business processes are directly linked to the reverse-engineered web services, resulting in a high degree of technology coupling. This in turn leads to a low level of maintainability and low reusability. The Model-Driven Architecture (MDA) provides an approach aimed at achieving technology independency through full top-down development. However, this approach does not handle the bottom-up reverse-engineered components very well. In this paper, an approach is introduced that combines top-down with bottom-up realization, while minimizing the technology coupling. This is achieved by an explicit buffer between top-down and bottom-up. “High-level” web services are derived through top-down development, whereas “Low-level” web services are reverse-engineered, and a mapping is created between the two. The approach focuses on engineering web services reversely, while retaining the advantages of the MDA with respect to platform independency, maintainability and reusability.