Mezzmo is a server, so it delivers your media files to clients. Mezzmo does not have a built-in player, but it does have a built-in DLNA client that you can use to browse other servers and add files from those servers to the Mezzmo database (this is what we call NMSS) so that those files are available to your client devices through Mezzmo as well.

WMP is a client and it can connect to Mezzmo and play files.

Can you please describe to me in a bit more detail what you're trying to achieve and what the actual problem is, because I'm not really sure I understand. Sorry Are you trying to stream files located on one machine using Mezzmo to another machine that has WMP on it to play through that WMP?