I've generated the components.VScrollSkin with Flash Builder using spark.components.VScrollBar as host component and created as a copy of spark.skins.spark.VScrollBarSkin
Whatever I change and do in components.VScrollSkin isn't applied when I build the app. Always the default Skin is shown. I've but a trace in components.VScrollSkin to see if it's actually being loaded or not. But it is being used.