グラフィック レイヤーのフィーチャ ウェイトを変更する方法

IMap pMap = pMxDocument.FocusMap;
IGraphicsLayer pGraphicsLayer = pMap.BasicGraphicsLayer;
IBarrierProperties pBarrierProperties = (IBarrierProperties )pGraphicsLayer;

pBarrierProperties.Weight = 0;	//0 = esriBasicOverposterWeight.esriNoWeight
Dim pMxDocument As IMxDocument
Set pMxDocument = ThisDocument

Dim pMap As IMap
Set pMap = pMxDocument.FocusMap

Dim pGraphicsLayer As IGraphicsLayer
Set pGraphicsLayer = pMap.BasicGraphicsLayer

Dim pBarrierProperties  As IBarrierProperties
Set pBarrierProperties = pGraphicsLayer

pBarrierProperties.Weight = 0