how to obtain ILabelEngineLayerProperties2 ? and error calling it's method

How do we obtain ILabelEngineLayerProperties2 ?

The only way I could figure it out is through IGeoFeatureLayer.AnnotationProperties which is collection of IAnnotateLayerProperties interfaces. Then I cast IAnnotateLayerProperties to ILabelEngineLayerProperties2 .

I think this is working for me, but I'm not 100% sure as I'm getting the following error calling
ILabelEngineLayerProperties2.BasicOverposterLayerProperties .

System.NotImplementedException: The method or operation is not implemented.
at ESRI.ArcGIS.Carto.ILabelEngineLayerProperties2.get_BasicOverposterLayerProperties()

suggestions?