The emerging trends for e-business engineering revolve around specialisation and cooperation. Successful companies focus on their core competencies and rely on a network of business partners for the support services required to compose a comprehensive offer for their customers. Modularity is crucial for a flexible e-business infrastructure, but related requirements seldom reflect on the design and operational models of business information systems. Software components are widely used for the implementation of e-business applications, with proven benefits in terms of system development and maintenance. We propose a service-oriented componentisation of e-business systems as a way to close the gap with the business models they support. Blurring the distinction between external services and internal capabilities, we propose a homogeneous model for the definition of e-business applications components and present a process-based technique for component modelling. We finally present an Enterprise Java Beans extension that implements the model.