Porting class constructor to a script

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Hi, everybody! I have a QtScript problem.
I have a following class to be imported to QtScript:
@
class CPos : public QObject, public QScriptable
{
Q_OBJECT
Q_PROPERTY(float x WRITE setX READ x)
Q_PROPERTY(float y WRITE setY READ y)
Q_PROPERTY(float z WRITE setZ READ z)

public:
CPos(QObject* parent = 0) : QObject(parent) {}
void setX(float value) {f_x = value;}
void setY(float value) {f_y = value;}
void setZ(float value) {f_z = value;}
float x() const {return f_x;}
float y() const {return f_y;}
float z() const {return f_z;}

private:
float f_x, f_y, f_z;
};

Q_DECLARE_METATYPE(CPos*)
@

I wrote the following functional to be called as class-constructor:
@
QScriptValue Pos(QScriptContext *context, QScriptEngine *engine)
{
QScriptValue value = engine->newQObject(new CPos());
value.setProperty("x", context->argument(0));
value.setProperty("y", context->argument(1));
value.setProperty("z", context->argument(2));
return value;
}
@

In my main functioan I do the following:
@
QScriptEngine engine;
QScriptValue proto = engine.newQObject(new CPos());
engine.setDefaultPrototype(qMetaTypeId<CPos*>(), proto);
engine.globalObject().setProperty("Pos", engine.newFunction(Pos, proto));
@

But as far as I can see my script

@
var p = new Pos();
@

has no effect. Where did I go wrong?