I believe, when deploying JBoss on AWS the only consideration is on the number of cores. Therefore, you can run it on AWS as long as you are under the standard license core limit that you purchased.
Edit: Looks like I was wrong about JBoss usage on cloud platforms. Please disregard my comment.
Take a read through our Cloud Access program information:
You are legally required to sign up for this no-cost program because the default agreement between RH and customers does not allow deployment to cloud environments. This program extends our agreement so you are covered.
I might add, we've done all our testing on EC2 with EAP 6, not EAP 5. If your application requires clustering, you may have issues with EAP 5.