Have you installed FtsContentProvider binding for file-storage? You have to do that for all the packages you want to be searchable.
To do this, go to yourdomain.com/acs-service-contract and click "install" for all FtsContentProviders you need. You might have to restart the server after that. Then add some content and try to search for it.
I'm not sure what you can search in file-storage. It might be that you can't at all search the contents of the stored files, just for their metadata. I'm not sure about this, tho.