Hi,

I found a solution my self:

NStyleSheet stylesheet1 = new NStyleSheet("Test");
stylesheet1.Style.StrokeStyle = new NStrokeStyle(0.1f, Color.Black);
stylesheet1.Style.EndArrowheadStyle =
new NArrowheadStyle(ArrowheadShape.Arrow,
"",
new NSizeL(2, 2),
new NColorFillStyle(Color.Black),
new NStrokeStyle(1, Color.Black));

nDrawingDocument1.StyleSheets.AddChild(stylesheet1);

The stylesheet "Test" may then be found as:

Connector1.StyleSheetName = "Test";