Business process modeling is a commonly used approach in the development of service oriented architectures. The previous research on this topic demonstrated that process-oriented models might be too rigid for dynamic adaptations of the business logic. Rule-based approaches are considered an alternative, which offers more flexibility thanks to the declarative nature of rules and their underlying reasoning algorithms. However, modeling a business process through rules is a tedious process for developers in terms of the overall business process comprehension. In this paper, we propose a hybrid solution - a modeling language that integrates both rule- and process-oriented modeling perspectives. The language (Rule-based BPMN -rBPMN) is based on the integration of the business process modeling notation with the REWERSE Rule Markup Language. In this paper, after introducing BPMN, we report on the experience in modeling of service-oriented architectures (SOA) from the perspective of message exchange patterns.