Using MC15.0.44
Tools -> Options -> Library & Folders -> Configure Auto-import -> Add -> Browse...
I'm presented with a dialog box that has no way to manually specify a location. In previous versions of MC there used to be a text field in that browse window. I used that to enter a UNC path, one that wasn't otherwise visible in the browsing lists.
Please being back this functionality. Or at least provide some other way to edit the UNC path for a watched import folder.