moc generated code fail to compile if QObject is inherited virtually

class KopetePasswordRequestBase : public virtual QObject
{
	Q_OBJECT
signals:
	void requestFinished( const QString &password );
public slots:
	virtual void walletReceived( KWallet::Wallet *wallet ) = 0;
    virtual void gotPassword(const QString&, bool) =0;
	virtual void slotCancelPressed() =0;

};