You have to set up network shares and set all database location as UNC paths not as direct locations on the server. Here is a post on UNC paths. Though it is for music, the same idea can be used for all databases.
http://www.xlobby.com/forum/viewtopic.p ... hlight=unc
What this means, in AMC you could try and select the location of your coverart by going through a network share to the location of the coverart. This way that info should be capture in the database, and when it is copied over to the fat client, you should be able to see your coverart then.
So if looking at the database in XLobby/Setup. Where it say Coverart: and then in the window show the location of the coverart. Instead of C:... you will want to see \\"Computer"\location, where "Computer" is the network name of your server and location...well you get the idea.
Hope this helps.
*EDIT*
Actually what may work is if you go to the XAnt.ini file, and there enter the UNC network paths to the locations of the images. That may work as well, though I haven't tested it that way before.