how do I set the caption backbrush property at the bottom?

MindFusion.FlowChartX.Table textBox2 = strategyFlowChart.CreateTable(rect.X + 36 + xoffset, rect.Y + 20 + yoffset, 10, 10);
textBox2.EnableStyledText = true;
textBox2.Selected = false;
textBox2.AttachTo(textBox, MindFusion.FlowChartX.AttachToNode.BottomRight);
textBox2.Locked = true;
//textBox2.Style = MindFusion.FlowChartX.BoxStyle.Shape;
//textBox2.Shape = MindFusion.FlowChartX.ShapeTemplate.OffpageReference;
strategyFlowChart.Add(textBox2);

IndicatorGroupNode BnodeType = new IndicatorGroupNode(textBox2);
Group Bgroup = _editorStrategy.CreateIndicatorGroup();
BnodeType.Group = Bgroup as IndicatorGroup;
Bgroup.Name = "P1-B";
textBox2.Caption = "P1-B";
textBox2.FillColor = Color.Moccasin;
textBox2.CaptionBackBrush = ??????