How can I use self implemented Widget in self implemented QDeclarativeItem ?

[aabc]

I know how to use Qt C++ object in Qml (Inherit QDeclarativeItem and implement). I know how to implement my own widget (Inherit QWidget and implement). I also know how to use Qt widget (like QPushButton) on my self implemented QDeclarativeItem and see it in QML.
My problem is - I dont know how to use my own implemented QWidget in my own implemented QDeclarativeItem.

[andre]

I would suggest, that that would work in the same way as using a standard Qt widget in QML... What is different, exactly?

[aabc]

The showEvent isn't called and therefore my widget isn't shown.
With Qt widget (like QPushButton) the showEvent is called and the QPushButton is shown.