Holonic and Service-oriented Architectures have been proposed as solutions for the conception of flexible and reactive systems. Flexibility, being one of their main objectives, depends greatly on the way information is presented in the system which can limit the flexibility of higher levels strategies as in process planning and reconfiguration. Although many works propose the use of services, none have been found describing what services stands for in a manufacturing context or how these can form manufacturing processes. This paper proposes a methodology for designing manufacturing-process specifications based on workshop-services that welcomes product customization and suitable for product driven applications. Conceptual models for processes and services are proposed in this work designed to preserve the fractal characteristics of products and processes and facilitate service reutilization. Such models form part of specification framework that will serve as a reference for the design and conception of manufacturing processes and services in Service-oriented Holon-ic Manufacturing Systems.