This paper specifies how to define the technical and semantic link that allows transform a business object model in a set of Web services. The business object model represents the set of things, entities or resources that handles, generate or consume business processes. A Web services model describes the set of software services that make Web applications integrated and coherent; these applications are necessary to support the implementation of the business processes and contribute to achieving business goals. The proposed transformation strategy makes the specification of technical and semantic relationship between objects and Web services, from two complementary perspectives: (1) refining the organizational task to define technical details, that is, from the business processes level to the technologies level; and then, (2) verify this relationship and semantically validate it in reverse order, i.e., abstracting the support to the business work from the defined Web services. The described specification process is evolutionary as several repetitions of the refinement and abstraction effort is required to achieve a balanced and representative specification of the relationship between business processes and Web services.