Hi Sub,
RadChart exposes such properties as it allows appearance customizations as well -- they are not based on CssClasses but on setting various properties across the control elements (you can then serialize and deserialize these modifications in xml skins for future use).
You can find more information on chart styling in the online help
here (topics in Controls >> RadChart >> Styling RadCharts folder).
Sincerely yours,
Manuel
the Telerik team