This paper presents automatic generation of use cases as an alternative both to speeding up requirements elicitation and formalizing the obtained use cases to approach the requirements reuse. We propose a framework for requirements documentation as use cases that might be included in coarse grain reusable structures. In order to effectively integrate the software requirements in reusable components, adequate models promoting reusability are required. Hence, we accomplish the requirement elicitation through a process usingWorkflows and Petri nets. This process gives an analytical treatment to system requirements which are stored in a repository.