What actually VisualStyle builder does is to modify the CSS of an existing skin and not changing the sprite image the skin for the particular controls uses.
RadButton ButtonType="StandardButton" uses sprite image for its background, and therefore in order to modify it you must:
- either modify the existing sprite image of the RadButton.
- or create a new one.
If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the RadControls for ASP.NET AJAX, subscribe to the blog feed