[Zubersoft]

The reason that works is because Google is asking for other apps to provide them a file to access, and then they internally upload that file to their service. That is the equivalent of using Import->System File Browser in MobileSheetsPro. If you do that, you should certainly see your file manager application show up and you can access your NAS to import files. It's just when it comes to creating/saving files that there is a problem.

Mike