Hi Cesar,
you have to use the IP of the core (-s = server). You can define the MAC address for sueezeslave using "-m", you can use whatever you want, best is, if you start with 00:00:00:00:00:01 and increase this MAC address for every other squeezeslave. To use this player within LMCE add this as described in the wiki and use the MAC address you have used for the daemon. I don't know the url right now, but you can connect to slimserver on your dcerouter using a browser. If your squeezeslave has connected successfully you should see it in the "player" section. From within this section you should see if your squeezeslave is running, what is playing, etc.
eNoodle