Languages for aspect-oriented programming (AOP) [5], such as AspectJ, are now popular, and the concepts used by the AOP community such as join points, pointcuts and advices are well-known. At the same time, in recent years, the aspect oriented software development (AOSD) approach has been developing itself beyond the programming activity. More particularly, the Early Aspects Initiative [9] advocates the management of crosscutting properties, i.e. aspects, at the early development stages of requirements engineering and architecture design to identify the impact of aspects as soon as possible. Some composition operators of aspects exist for these development stages [1][2], but they do not closely match standard AOP concepts (pointcuts, advices...). In this paper, we propose an automatic way for weaving behavioural aspects given as scenarios.