[OPM CE C#] How to place optional components?

Hello All,

I can place components as below:

                PipeFlangeComponentData flange1Data = new PipeFlangeComponentData(PipeFlangeType.WELD_NECK_FLANGE, specification, nominalDiameter);
                PipeFlangeComponent flange1 = new PipeFlangeComponent(new DPoint3d(1088.9, 0, 0), flange1Data, Math.PI, DrawingView.ViewTop, true);
                flange1.Create();

But it seems it can place the first flange only. If there are multiple flange with same EC_CLASS_NAME and size, how to place the other flanges?

Thanks.