@ta_neo. Thanks for your interest in the plugin. As it is right now, unfortunately, it may not show a folder outside of the Joomla directory. There may be a way to edit it slightly to do this, but I have not tried or tested it. So, I cannot guarantee that.
I think some persons have tried making a symbolic link (shortcut) in the Joomla folder that point to another location. However, I have not tried it, so I don’t know how that would work out exactly.
Please have a look at this post for more info: http://support.michaelgilkes.com/topic/symbolic-link