You would need to install a full channel. Get one from Stomp's Wii MC thread. I think Emuhack is the one who made the full channel (should be included in stomp's first post).
WiiMC --Wii Media Player
Edit: It is included, look for the quoted post by emuhack in the first post of that thread. Those are the full channels. Copy the .wad to SD card and install with wad manager.