Access to the same class instance from qml - class

Question

I'm using Qt 5.1.0 and QtQuick 2.0.
I've just learned how to exchange data and method between qml and C++. In detail, I want to expose a (nested) structure, so I created classes which contains the required properties and methods.
It works, but I cannot share the very same instance between C++ and qml. Changing something from C++ side leads to no changes in qml side.
A short example:
main.cpp
#include <QtGui/QGuiApplication>
#include <QtQml>
#include "qtquick2applicationviewer.h"
#include "myclass.h"
int main(int argc, char *argv[]) {
QGuiApplication app(argc, argv);
qmlRegisterType<MyClass>("MyLibrary", 1, 0, "MyClass");
MyClass *myclass = new MyClass();
Category *cat = new Category();
cat->setName("foo");
myclass->append(cat);
qDebug() << myclass->categoriesCount(); // returns 1 OK!
QtQuick2ApplicationViewer viewer;
viewer.setMainQmlFile(QStringLiteral("qml/main.qml"));
viewer.show();
return app.exec();
}
myclass.h
#include <QObject>
class Category : public QObject {
Q_OBJECT
Q_PROPERTY(QString name READ name WRITE setName)
public:
Category() {}
QString name() const { return m_name; }
void setName(QString name) { m_name = name; }
private:
QString m_name;
};
class MyClass : public QObject {
Q_OBJECT
Q_PROPERTY(QList<QObject*> categories READ categories NOTIFY categoriesChanged)
Q_PROPERTY(int categoriesCount READ categoriesCount)
public:
QList<QObject*> categories() const { return m_categories; }
void clear() { m_categories.clear(); }
void append(Category *category) { m_categories.append(category); }
int categoriesCount() const { return m_categories.count(); }
private:
QList<QObject*> m_categories;
signals:
void categoriesChanged();
};
main.qml
import QtQuick 2.0
import MyLibrary 1.0
Item {
id: root
width: 360
height: 360
Text {
id: foo
text: myclass.categoriesCount // writes 0 -> should be 1
}
MyClass {
id: myclass
}
}
I'm afraid the qml engine accesses to a different instance of the class myclass created in the main file.