Installer deleting "desktop.ini" file

I'm using folder customization for faster folder visual location, so I dedicate "appicon.ico" to be folder icon for every "AppNamePortable" folder.
In that folder windows creates "desktop.ini" file with "hidden" and "system" attributes, but it is deleted by installer whenever I update application.
It is not deleted if in "installer.ini" is statement:

[FilesToPreserve]
File1=desktop.ini

But then I have to make my own installer for every update of every application and could not use update from platform.
Could it be possible, in some next release, to default installer not to delete files in "AppNamePortable" folder (I could not find any environment variable substitution for that folder).

Another problem is that missing environment variable named like ALLUSERDOCUMENS which would act like ALLUSERSAPPDATA but for Documents:
In Windows XP and 2000 it would be e.g. C:\Documents and Settings\All Users\Documents
and in Vista, 7, 8, 10 it would be e.g. C:\Users\Public\Documents

Some programs are using that folders to put there data which are available for all users, and I could not find way to backup/restore those folders.
Any solution or suggestion would be appreciated.