I cannot export / import files between iTunes and iPhone apps documents folder

When select App that allows import/export of documents between iTunes and iPHone, I click Add button and select file from Finder it does not appear in the list, apparently nothing happens, as the file do not appear on device also. The same thing about exporting file from iPhone app to Mac with iTunes, files are written in documents folder and I can use them inside my Application and device, but do not appear in the iTunes list. Feature does not work for all the apps I've installed, including to Adobe Acrobat, FileApp Pro, Documents, and several other.

What can be done in order to fix this issue and get document sharing to work?