Mobile Home directories

I have a question about how mobile home directories work. I have my users in AD and my home directories on an XServe. I have set the connection to afp. The problem is when I set the AD plugin to use mobile home directories, I get the dialog asking if I want to create a modile account, but when I click "Yes" the mobile account home folder that is created is NOT the same as the home folder on the server. Can someone explain how the mobile home directories are created/synced. Shouldn't I see the same home folder that is on the server? Thanks!