If the folder was created previously, right-click the newly created library path, and then click Add Proxy Path. Browse to the folder location and select it.
For custom iPart factories only, enter a location for the iPart factory proxy file. A proxy folder is created automatically with the same name as the iPart factory library, but with a leading underscore (_) character.
If the proxy folder does not exist, use Microsoft Windows Explorer to create it before you add the proxy path. You can click Add Path again, and specify the new folder path. Name the new library the same as the iPart factory library, preceded with an underscore character.