Rally Software

I am trying to understand how CA Agile Central treats Features versus User Stories.  I am trying determine a process by which a Release is built from the backlog and the iterations are built from the stories in the Release.   However, it would appear that only a Feature can be put into a Release since I do not see any of the user stories show up as a the backlog in the Release planning page.

Can anyone point me at some good documentation on this topic? 

I'd start with the help topic on Timebox-Based Planning. Release Planning is intended for planning features as you've observed, and Plan >> Team Planning, Plan >> Backlog and others are where you can see and manage your backlogs and Release backlogs. Hope that helps.