How to support/assing ALL file types (UTIs) in iOS?

Question

I'm developing something like file manager for remote filesystem with some basic operations including transferring file(s) between server and iPad and viewing them.

In order to be useful I need my app to open all types of files from other apps (like Mail, Safari, etc.) via "Open in.." dialog to get them into my app, i. e. Dropbox-like behaviour. When I use public.data and public.content, like it is described in this answer (and this), it sometimes work, but most of the time, it isn't. Moreover, iOS 6.1 simulator behaves nondeterministic regarding file handling.

When I Run in Xcode and it launches simulator, it doesn't work. When I let simulator running, Stop in Xcode and then Run in Xcode, it suddenly work. When I completely quit simulator and Run in Xcode I get at start of this loop. Mysterious.

When I run app on physical iPad with iOS 6 and start Safari or Mail and go to some document or attachment in it, [Open in...] dialog appears including my app but tapping does nothing, no reaction.

My goal is to make it work for iOS from 5.1 up.

• Base SDK: iOS 6.1
• Target: 5.1

I'm rookie here on SO. Although I've read instruction how to write good questions, help me improve my question if you feel it is needed, please.

Answer 1

Using public.item, in documentation:

Documentation UTIs