For multi-bitrate streaming, Flash and AIR media players request an F4M manifest file that contains the location and bitrate of each live stream. This type of F4M file is called a set-level manifest. In your case the set-level manifest is the Manifest.xml. When you access a stream via the stream name the manifest file is generated by FMS. To use the manifest file specified in the event access the streams via the event name as so : http://myserver.com/hds-live/livepkgr/_definst_/liveevent.f 4m.
Hope this helps.