Windows Libraries are a very useful feature. Unfortunately you cannot add certain locations like Network locations and other non-indexed locations to it easily. But a free software called Win Library Tool makes things easy.
Win Library Tool
Add Network Location to Windows Libraries
You can always add Network Location or any non-indexed locations to Windows Libraries using the command line utility slutil.exe programatically, but freeware Win Library Tool lets you do so easily.
Win7Library Tool lets you add network (UNC or mapped drive) and any other un-indexed folders to Windows Libraries.
It also lets you backup library configuration, such that a saved set of libraries can be instantly restored at any point, allows you to create a mirror of all libraries (using symbolic links) in [SystemDrive]:\libraries, and even change a library’s icon.
Check it out at it download page.