From an agile perspective, integrating Arquillian and JBehave makes good sense, which is why a number of developers have already written open source extensions that bridge the two frameworks. Get introduced to three such extensions (one of them written by the author) and see how they can incrementally improve the experience of behavior-driven development with Arquillian. Who knows, one of them could be the missing piece you've been looking for -- or the foundation for your next open source project.
Arquillian is a Java EE integration testing framework that executes tests in the container, testing not just your core application but its interaction with business components. While Arquillian makes writing functional tests much easier, I found it lacking in support for behavior-driven development (BDD). Specifically, I wanted to create a bridge between Arquillian and JBehave, the popular BDD testing framework.