Why are shadow options disabled for all light types

Hi

Why are shadow options disabled for all light types (direcional/point/spot)? I've got global quality set to 'beautiful' and all relevant objects have shadows cast/receive set on.

Thanks

Steve

Mac OSX 10.6.3 Unity 2.6.1

Dynamic shadowing is only available in the Pro version of Unity.

See the License Comparison page, for a list of Pro-only features.