As of my own experience it might help to add symbolic links to those folder /media/hd5a and /media/hd4a
place the symbolic links in /home/public/data/videos/
You should check that it has read permissions as well i guess.
I already tried that, but it didn't seem to work. I added a symbolic link to one of the drives and then from the admin page clicked "resynchronize" I believe. A script was run and it said that the contents of the folder was added to the database or something like that. I could see it processing the names of my ISO files, so I know my link was good. I thought that I was in the clear until I tried to view the files from LMCE. When I select the 'videos' menu my ISO images aren't listed.
I tried ripping a DVD from inside LMCE and that worked fine. The movie was listed and I could select it.
I'll try it again tonight and check the permissions of the symbolic link.