Plot bands labels - charts

Hi,
I´m trying to build a chart like this one :http://demo.vaadin.com/charts/#SplineWithPlotBands, but I need that te labels of the plotband apear before the data series (if they appear behind them it´s difficult to read).
I´m using clases: PlotBand, PlotBandLabel and DataSeries. DataSeries and PlotaBandLabel classes don´t have Zindex atribitue.

Thanks,
Germán