Software architectural description languages (ADLs) are used to specify a high-level, compositional view of a software application, defining how a system is to be composed from coarse-grain components. ADLs usually come equipped with a rigourous state-transition style semantics, enabling formal understanding of distributed and event-based systems [6]. However, additional expressive power is required for the description and understanding of enterprise-scale software architectures - in particular, those built upon newer middleware, such as implementations of Java’s EJB specification [2] or Microsoft’s COM+/.NET [8]. Such middleware provides additional functionality to a configuration of components, by means of a context-based interception model [12]. We explore an ADL that can define architectures built upon such middle-ware. In this paper, we focus on modelling transactional architectures built on COM+ middleware.