public CIMSymbolReference SoftEdgeSymbol {get; set;}

{
  var breaklineRendererDef = new TinBreaklineRendererDefinition();
  // use default symbol for regular edge but specific symbols for hard,soft,outside
  breaklineRendererDef.HardEdgeSymbol = hardEdgeSymbol.MakeSymbolReference();
  breaklineRendererDef.SoftEdgeSymbol = softEdgeSymbol.MakeSymbolReference();
  breaklineRendererDef.OutsideEdgeSymbol = outsideEdgeSymbol.MakeSymbolReference();
  // Note: Needs QueuedTask to run
  {
    if (surfaceLayer.CanCreateRenderer(breaklineRendererDef))
    {
      CIMTinRenderer renderer = surfaceLayer.CreateRenderer(breaklineRendererDef);
      if (surfaceLayer.CanSetRenderer(renderer, SurfaceRendererTarget.Edges))
        surfaceLayer.SetRenderer(renderer, SurfaceRendererTarget.Edges);
    }
  }
}