Plex Media Server Streaming Live From Windows Media Center

Have a Roku 3 streaming from WHS 2011 with Plex media server. Planning to buy Ceton TV tuner. Should I run WMC direct on WHS 2011 or do I need another client to manage recordings?

Does anyone know if Plex can start streaming directly from WMC or if it needs a media file that has stopped recording?

Have only old PC clients and think Roku is cheap Plex extender.

Thanks