Setting data in Writer chart from Basic

Hi,

with this code I can change the data in a Writer chart:

    set doc = thisComponent
    set ctrl = thisComponent.CurrentController
    xChart = ctrl.getModel().getEmbeddedObjects.getByName("Objekt1")
    set cDoc = xChart.getEmbeddedObject
    set cDataArray = cDoc.getDataProvider
    data = cDataArray.getData
    ' Do something with the data
    cDataArray.setData(data)

But I can't get the chart to update. The only way I see is to
double-click on the chart in the document, then it will update.

What is the right way to force an update via code?

Thank!
    Jan