qwt, how to fill area above a curve with color?

[ConfaMiky]

Hi all,
Colud aomeone help in qwt fillCurve using?
I try to fill the curve below and over the baseline with different color. I try to use the code that I found and for clipping different regions it's ok.
But I'm not been able to fill it with different color could someone help me. I try with setBrush(...) but nothing happen.
Thanks miky.

@
void Curve::fillCurve(QPainter *painter,
const QwtScaleMap &xMap, const QwtScaleMap &yMap,
const QRectF & canvasRect, QPolygonF & polygon) const
{
painter->save();
QBrush *brush1 = new QBrush (Qt::green, Qt::SolidPattern);
setBrush(*brush1);
painter->setClipRect(0,yMap.transform(baseline()),1000,1000,
Qt::ReplaceClip);
// QwtPlotCurve::fillCurve(painter, xMap, yMap, canvasRect, polygon);

painter->setClipRect(0,0,1000,yMap.transform(baseline()),
                     Qt::ReplaceClip);
QwtPlotCurve::fillCurve(painter, xMap, yMap, canvasRect, polygon);
painter->restore();

}@