Qt / QML set property from c++ class for GridView

First i created a new c++ class with a member function, which is giving back a string:

#ifndef TESTNAME_H
#define TESTNAME_H

#include <QObject>
#include <QString>
#include <QVariant>


class testname : public QObject
{

    Q_OBJECT;

public:
    testname();
    Q_INVOKABLE QString getName();
};

#endif // TESTNAME_H


#include "testname.h"

testname::testname()
{
}


QString testname::getName() {

    return "sometext";
}

I have a qml file with only a text in the middle, like this:

import QtQuick 1.1

Rectangle {
    width: 360
    height: 360

    Text {
        id: text1
        anchors.centerIn: parent
        text: testqml
        font.pixelSize: 12
    }
}

Notice that the property "text" is a variable named "testqml". This variable contains the string returned by the function of the class i showed above. The code for this is in the main.cpp:

#include <QApplication>
#include "qmlapplicationviewer.h"
#include <testname.h>
#include <QDeclarativeContext>
#include <QDebug>

Q_DECL_EXPORT int main(int argc, char *argv[])
{
    QScopedPointer<QApplication> app(createApplication(argc, argv));


    // Create instance of "testname"
    testname *test = new testname;

    QmlApplicationViewer viewer;

    viewer.rootContext()->setContextProperty("testqml", test->getName());

    viewer.addImportPath(QLatin1String("modules"));
    viewer.setOrientation(QmlApplicationViewer::ScreenOrientationAuto);
    viewer.setMainQmlFile(QLatin1String("qml/classtest/main.qml"));
    viewer.showExpanded();

    return app->exec();
}

Using the setContextProperty-Function, the returned string is exposed to the qml file and is correctly shown in the running program. But i'm actually intending to inherit a model for a GridView. So i created a Gridview with one list element in QML:

import QtQuick 1.1

Rectangle {
    width: 360
    height: 360

    GridView {
        id: grid_view1
        anchors.centerIn: parent
        width: 140
        height: 140
        cellHeight: 70
        delegate: Item {
            x: 5
            height: 50
            Column {
                spacing: 5
                Rectangle {
                    width: 40
                    height: 40
                    color: colorCode
                    anchors.horizontalCenter: parent.horizontalCenter
                }

                Text {
                    x: 5
                    text: name
                    anchors.horizontalCenter: parent.horizontalCenter
                    font.bold: true
                }
            }
        }
        model: ListModel {

            ListElement {
                name: testqml
                colorCode: "grey"
            }


        }
        cellWidth: 70
    }
}

The variable "testqml" is now in the "name" Field of the List, which is in the example a string. If i use a string "likethis", it is correctly displayed. But if i run my program (main.cpp and class are remaining unchanged) i get this error:

ListElement: cannot use script for property value 
                     name: testqml 
                     ^ 

Now i'm stuck. I found an reported bug with a similar issue #QTBUG-16289, but i don't know how to solve my problem. Any ideas, how-tos, tutorials or something to solve my problem?

Thanks and regards :)