Mounting Network Home in Dock through Workgroup Manager

Hello, I am currently running workgroup manager on 10.6.8 Server. I have 10.7 clients, and I would like to add their network home folder to the dock. Within workgroup manager dock preferences, I have checked the box for Add other folders: Network Home. When a user signs in, the network home is on the dock, but shows up as a question mark, and does not respond at all when clicked. Nothing appears from the icon, and no dialogue boxes appear. Has anyone else experienced this problem, or is there something simple I am missing here?