Using PaletteProvider with z-value as type corresponding to a color

I have a chart with FastImpulseRenderableSeries.

<s:FastImpulseRenderableSeries StrokeThickness="3" SeriesColor="LawnGreen" x:Name="IdentifiedPeakSeries" YAxisId="PeakAxis">
            <s:FastImpulseRenderableSeries.PointMarker>
                      <s:EllipsePointMarker Width="0" Height="0" Fill="LawnGreen"/>
            </s:FastImpulseRenderableSeries.PointMarker>
</s:FastImpulseRenderableSeries>

The color of each Impulse depends on a own type of each result. There are three different types which should have color green, yellow and red. In the program I use the XyzDataSeries to set the x and y values of the impulse and the z-value as the type to get the color.

var seriesId2 = new XyzDataSeries<double, double, int>();

for (int i = 0; i < SamplePeakList.Count(); i++)
{
         seriesId2.Append(SamplePeakList[i].Mass / 1000, SamplePeakList[i].Intensity, peakType);
}

But the IPaletteProvider has no overridable method with x, y and z value!
How can I pass the impulsetype to the palette provider to set the corresponding color?