I used second link as base. That code makes application can't close (background for ever and ever).
After I did this (for reference to other users):
Next reference allows configure minimize button (a method, it can be integrated to QML).
in .h of my C++ class (to be integrated with QML) and next line in body of method which will be called from QML (p.e. a C++ method which will be called in ToolButton for hide/minimize).
In .pro add:
Only for further reference I think it can be improved, but it's fully functional in Symbian Anna tested on E7-00
LIBS += -lws32\