How to do backup from network shares

Hi to all,

I have on a backup server BE2012 installed.

generally I use Disk-to-disk-to-LTO5 Autoloader strategy to do my backup.

Now I need to include some shares in backup process that are on a NAS.

I have mapped the share as network drive but BE2012 don't see it and I don't have also possibility to explore my network.

How can I do?

Thanks to all, 

Alex.