Why not insert the oldest disk into the Stardom itself so that it is recognized by BE as the original storage ?
The other option may work. Copy the contents of the oldest disk into a network share except the changer.cfg, folder.cfg files. Try creating a Disk Storage from BE's interface now and point it to this network share. If this gets added successfully, run an inventory and catalog of the storage device and check if the restore selections are available or not.
Though, I would still recommend putting back the oldest disk into the original enclosure and running a restore from there.