Serving user Sites dirs

With network home users, I want the content they place in their Sites folders to be served at domain.edu~/username . I’ve enabled

UserDir Sites

in the mod_userdir section of httpd.conf, and it’s working for half of our users, but not for the other half (they get 404s). The physical configuration is:

server 1 (web server)
server 2
server 3
RAID

One of the RAID’s banks is controlled by the server 2, the other bank is controlled by server 3. Somehow, it seems like the web server is only aware of the location of user homes on the half of the RAID controlled by server 2. How can I make it aware of the user homes on the half of the RAID controlled by server 3?

I don’t think it’s a matter of simply mounting the RAID as a share to the web server, since homes are defined as afp locations, and mounting isn’t necessary for the 1st half of the RAID. So… what else should I be checking here?

Hope that’s not too convoluted. Thanks in advance,
Scot