set Application icon from script for build?

I create my own editor that has functionality to build the apps from script, I need to change to application icon from script, how to do it correctly. currently I'am doing like this:

 var texImporter : TextureImporter = TextureImporter.GetAtPath(AssetDatabase.GetAssetPath(getAppState().appIcon));
 texImporter.isReadable = true;
 AssetDatabase.ImportAsset(AssetDatabase.GetAssetPath(getAppState().appIcon));
 
 var sizeList : int[] = PlayerSettings.GetIconSizesForTargetGroup(BuildTargetGroup.Standalone);
 var iconList : Texture2D[] = new Texture2D[sizeList.length];
 var ndx : int = 0;

 for(iconSize in sizeList){
     iconList[ndx] = Instantiate(getAppState().appIcon);
     iconList[ndx].Resize(iconSize,iconSize,TextureFormat.ARGB32,false);
     ndx++;
 }

 PlayerSettings.SetIconsForTargetGroup(BuildTargetGroup.Standalone,iconList);

but the icon does not change.