Are you using TVersity as your main Media Server on your PC? It should be simply a matter of sharing your media locations in the TVersity GUI then select TVersity as your Media Server on the SL300i and your good to go. (Once TVersity has catalogued references to your media in it's DB)
Add a folder (your drive location etc) and give it a title
C:\My Music (My Music)
C:\My Pictures (My Pictures)
C:\My Videos (My Video)
WMP11, TVersity and PMM can co-exist on the same PC, but it's better to only have one underlying media server service running at a time.
With WMP11 are you talking about the underlying Windows Media Connect? Can you just switch it and PMM off?
Do read the TVersity support page and FAQ for more information on setting up TVersity correctly on your PC http://tversity.com/support/