We describe how Event-Condition-Action (ECA) rules can be combined with Process Algebras like CCS as specification of the action part to obtain a powerful, declarative formalism that also covers intuitively procedural tasks in an appropriate way. Since both formalisms have a concise formal semantics, verification and other kinds of reasoning about such specifications are possible. Using a rule markup with cleanly distinguished rule components allows for such a compositional approach. The approach is currently under implementation in a General ECA Framework for the Web and the Semantic Web.