Modern software components are asked to deliver their services over different communication channels and devices to support mobile and ubiquitous applications. Therefore, development processes that traditionally address only functional requirements must be revised by considering new aspects: quality of service (QoS), user profiles and technical characteristics of channels. Moreover, services obtained by the composition of simple services offered by different providers are getting growing importance. In this paper, we propose a hybrid technique to deal with quality evaluation in composite Web Service design. This work extends and integrates the single-service design process presented in previous papers.