How to use VS 2012 / TFS for requirement engineering

Hi,

we are moving from waterfall to agil. We have already a lot of requirements with associations between them. For requirements analysis  with the business people we need still the old styled requirements / actors etc.

The question is, what is the most suitable mapping, how to put and how to visualize requirements, actors and use cases in  VS 2012 / TFS 2012 ?

Mapping

1. Requirement = ?
2. UseCase = StoryBoard (?)
3. Actor = ?

Thanks a lot in advance,

Michel