Once you have uploaded a feature class to the repository and open the feature class from the repository, you can determine the type of feature it is using with any of the ArcGIS Server APIs. For example, in the Flex API, you can check the type property in the Geometry class to figure out whether the feature geometry type is a point, polygon, extent, etc. However, there isn�??t a way currently to specify metadata for a FolderItem to specifically find out whether a trade area is of type drive time, simple ring, or a custom polygon. Maybe you could use a specific nomenclature for the repository item name to determine the type of trade area or add any metadata as part of the feature's attributes.