Multiple axes with a relation

I have an x axis which has its units in metres. I want to attach another x axes which shows units in foot. Right now I have 2 curves, 1 for each of the axes, getting painted one over the other.
Is it possible to have 2 axes with a known relation(like foot - metre) and have a single curve?

Code:

---

class YourPlot: public QwtPlot
{
    YourPlot( ... ):
        QwtPlot( ... )
    {
         ....
         enableAxis( QwtPlot::xTop );
         connect( axisWidget( QwtPlot::xBottom ), 
             SIGNAL( scaleDivChanged() ), SLOT( syncScales() ) );
    }
 
    void syncScales()
    {
        const QwtScaleDiv scaleDiv = axisScaleDiv( QwtPlot::xBottom );
 
        const double min = scaleDiv.lowerBound() * ...;
        const double max = scaleDiv.upperBound() * ...;
 
        setAxisScale( QwtPlot::xTop, min, max );
    }
}

---

Then attach your curve to xBottom.

Uwe