sender, RenderBeginEventArgs args)
//single value parameter
//multi value parameter
Although the values in the example are hardcoded you can take the actual values from your Silverlight UI controls. Notice that passing multiple values is achieved through an object array. In all other cases the value is set directly with its actual type.
Have in mind that this is one of the ways to accomplish the desired functionality and our ultimate goal is to provide a more sophisticated approach (e.g. Silverlight Report API) to build a report definition on the client and send it for processing on the server.
The new functionality is available in the internal build from Dec 3, 2009 and will be present in the subsequent official release. You can download it from the Latest Internal Builds page (login required).