QSetting doesn't work properly with SystemScope in Mac OS X Lion

There is a problem with QSettings from Qt 4.7.3 that is reproducible only in Mac
OS X Lion.

To work with system-wide application settings I write the following:

QSettings theSettings(QSetting::SystemScope, theCompanyName,
theApplicationName);

Normally on Mac these settings are stored in file
'Library/Preferences/com.CompanyName.ApplicationName.plist'. However starting
from Mac OS X Lion the file doesn't appear in this place. This is probably
because starting from Lion there are different default permissions for the
folder /Library/Preference. In Lion only root have write permission for this
folder while in previous Mac OS X versions admin users were also able to write
into this folder. So for me it looks like a bug in QSettings because the way it
is implemented now the QSettings object is just not usable in case an
application wants to store system-wide settings in Lion. I think QSettings should not
put the plist file into this folder starting from Lion, but use some
other place for the file.

To reproduce the problem you can use standard Settings Editor Example from the
Qt package.