// create layer
            this.TrackingLayer = new InMemoryFeatureLayer();
            this.TrackingLayer.Open();
            this.TrackingLayer.Name = TrackingLayerName;

            this.TrackingLayer.DrawingExceptionMode = DrawingExceptionMode.DrawException;
            this.TrackingLayer.DrawnException += new EventHandler<DrawnExceptionLayerEventArgs>(TrackingLayer_DrawnException);

            // add columns
            fscColumn = new FeatureSourceColumn("KeySymbol", "string", 116);
            this.TrackingLayer.Columns.Add(fscColumn);
            fscColumn = new FeatureSourceColumn("KeyItem",   "string", 32);
            this.TrackingLayer.Columns.Add(fscColumn);
            fscColumn = new FeatureSourceColumn("Label",     "string", 48);
            this.TrackingLayer.Columns.Add(fscColumn);

            // build spatial index
            this.TrackingLayer.BuildIndex();

            // close layer
            this.TrackingLayer.Close();



Here's how the feature is created.
                oTracking.ItemPoint    = new PointShape(myVertex.X, myVertex.Y);
                oTracking.ItemPoint.Id = oTracking.sKey;
                myFeature = new Feature(oTracking.ItemPoint);

                myFeature.ColumnValues.Add("Label",     oTracking.sLabel         );
                myFeature.ColumnValues.Add("KeyItem",   oTracking.sKey           );
                myFeature.ColumnValues.Add("KeySymbol", oTrackingLayerSymbol.sKey);