Unsolved QQuickView - singleton Component question

[cmessineo]

Here is my simple Singleton component:

pragma Singleton
import QtQuick 2.0

Item {
    id: va
    objectName: "va"

    property font my_font: Qt.font({
        family: "Arial",
                                   });

    property real version: 1;
}

How can I update the version property through C++ code?

I tried this, but to no avail:

QQuickItem obj = quickview->rootObject()->findChild<QQuickItem>("va");
...
obj->setProperty("version", "2");

quickview loads a qml file that includes the singleton component.

Thanks