QRubberBand make background invisible

[FlameFurious]

I'm trying to modify the painter method of QRubberBand to fit my taste of style, and for the most part it works just like it should, but I have tried to get the background to be invisible, but I have found no method that I had any luck with.

With no painting method for the background it is a transparent white.

class CustomRubberBand : public QRubberBand
{
public:
	CustomRubberBand(Shape s, QWidget * p = 0) : QRubberBand(s, p) 
	{
	}
 
protected:
	void paintEvent(QPaintEvent *pe) 
	{
		Q_UNUSED(pe);
 
		QPainter painter;
		QPen pen(Qt::red, 6);
		pen.setStyle(Qt::SolidLine);
 
		painter.begin(this);
		painter.setPen(pen);
		painter.drawRect(pe->rect());
		painter.end();
	}
};

class CustomRubberBand : public QRubberBand
{
public:
	CustomRubberBand(Shape s, QWidget * p = 0) : QRubberBand(s, p) 
	{
	}

protected:
	void paintEvent(QPaintEvent *pe) 
	{
		Q_UNUSED(pe);

		QPainter painter;
		QPen pen(Qt::red, 6);
		pen.setStyle(Qt::SolidLine);

		painter.begin(this);
		painter.setPen(pen);
		painter.drawRect(pe->rect());
		painter.end();
	}
};

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I've attached an example where you would be able to see what I'm talking about.
Does anyone know how to make it invisible?