Visual Annotate functionality

System

I am working with a client who wants to use TeamSite as the workflow engine to drive the creation and approval of assets with MediaBin. They have a requirement to be able to annotate directly on a file (preferrably PDF versions of the source inDesign files) to be able to circle mistakes and send those notes to someone else within TeamSite.
The client wants to use Visual Annotate for this, but I think Visual Annotate only works on HTML files. Is this true? Has anyone done annotations on PDFs with Visual Annotate? Can MediaBin convert inDesign files into HTML format?