N9, Qt C++ app (not QML,QtQuick!), screen orientation is locked to landscape mode.

I wonder how i could develop N9's application without using QML file .
I 've found some references from this, http://qt-project.org/forums/viewthread/9878

when i create a new project as the follow steps:
File > New File or Project > Qt Widget Project > Mobile Qt Application > Choose.
at last it finish create the project, but when i deploy it to the N9 ,the screen orientation is locked to landscape mode.
Which is so ugly,I want to know how to create a application in N9 which doesnt use QML file as the UI, and makes it good.

Some application ,like filebox and so on ,which doesnt use QML file ,how could they do this???

Sorry for my poor english.
Regards...