QDBus: Marshall user defined type (QPixmap) in QDBusArgument doesn't work

Hello,
in order to get familiar with the QDBus mechanism,
i made some examples derived from examples/dbus/complexpingpong.
I use Qt 4.4.0.
First I extended the example to user-defined structures containing "elemantary data types" to be marshalled by the DBus, they work fine.

Then, i tried to marshall a QPixmap-Object by the DBus,
I know this is not very usefull, but nevertheless i want to make this example work.

Problem: The server program has a segmentation fault and crashes.

Code:

---

inline QDBusArgument &operator<<(QDBusArgument &argument, const QPixmap &pixmap)
{
        QVariant variant;
        variant = pixmap;
        QDBusVariant dbusvariant = QDBusVariant(variant);
 
        argument.beginStructure();
        argument << dbusvariant;  // erroneous !!!!
        argument.endStructure();
        return argument;
}

---

Erro during execution of the server and client programs:
The serialization indicated above is run cyclically many thousand times, then the segmentation error occurs.

Has anyone a hint or an idea ?