sharing the wealth

I'm new at this but I tried to follow the directions with no luck. I use the Itunes program on the Mac and I am trying to get the itunes song files into my limewire library. I can only get files from limewire and my old napster files to show up in my library. In the setup wizard, it identifies where you have files you could share, the itunes program shows up, I select it, and they still don't show up in my shared files. How do I share my itunes files????