I would like to insert a reference plane using 3 3D points.

Here is my code and I don't know why it doesn't work. pleeeaaaase can you help me?

public void DrawSurface()

        {

            RefPlane myRefPlane = default(RefPlane);

            ModelDoc2 swDoc = ((ModelDoc2)(iSwApp.ActiveDoc));

            swDoc.SketchManager.InsertSketch(false);

            swDoc.SketchManager.Insert3DSketch(true);

            SketchPoint SkPoint1 = ((SketchPoint)(swDoc.SketchManager.CreatePoint(2,3,4)));

            SketchPoint SkPoint2 = ((SketchPoint)(swDoc.SketchManager.CreatePoint(4,1,2)));

            SketchPoint SkPoint3 = ((SketchPoint)(swDoc.SketchManager.CreatePoint(l1,1,1)));

            swDoc.SketchManager.Insert3DSketch(false);

            bool boolstatus;

            boolstatus = swDoc.Extension.SelectByID2("Point1@Esquisse3D1", "EXTSKETCHPOINT", 2,3,4, true, 0, null, 0);

            boolstatus = swDoc.Extension.SelectByID2("Point2@Esquisse3D1", "EXTSKETCHPOINT", 4,1,2, true, 1, null, 0);

            boolstatus = swDoc.Extension.SelectByID2("Point3@Esquisse3D1", "EXTSKETCHPOINT", 1,1,1, true, 2, null, 0);

            myRefPlane = ((RefPlane)(swDoc.FeatureManager.InsertRefPlane(4, 0, 4, 0, 4, 0)));

}