Some further info that may help in understanding all this.
Online and mounted are not the same thing. Online is a specific LMCE state, where by a device is marked as "online" in the database, which can then be used in SQL queries to filter which media to display. Whereas, mounted is the underlying Linux concept, where a storage device is mounted into the /mnt/ folder (and symlinked into the correct location under /home/....)
Mounting is handled automatically (by autofs I think) as and when there is access to a given folder - even if that is just a terminal session CD'ing into the folder... hence Andrew's advice.
Thus a share can be both Online and not mounted at the same time. The Online status indicates that the share is available if _needed_, however it won't actually be mounted until something tries to access it. The Online status is checked and set by the StorageRadar, and it is this that will affect whether media is displayed or not, the underlying mounting, done by autofs, is purely functional and should be transparent to LMCE itself. However, as Andrew pointed out, with more than one share, the autofs system has a bug which means that it doesn't mount properly. The terminal/cd approach should fix that. Once that is resolved you can concentrate on keeping the device marked as Online....
I'm not sure what triggers StorageRadar, or whether it is just a periodic thing, but that would be the place to start. You should read through the scripts that implement this and even run them from the command line to try to identify where it thinks your shares are offline rather than online. Not sure exactly which script is responsible for which function, but it should be one of: