You can use UriReportSource for SubReport item and select the report file (.trdx).
When you use such report definitions it will search the subreport .trdx file near the base path of your application. In your case you can update the main report definition to use XmlReportSource
and set the binding expression to the field containing the subreport XML as stated in our documentation
. This update can be made in the main report XML before you save it in the database, or in run-time when you deserialize the main report.
In this case, the users will create separate .trdx files, use UriReportSource and upload all the files to your server, you will alter the definition and then save them to the data-base.
Finally, I want to tank you for pointing out the wrong tooltips.
the Telerik team
Have you tried the new visualization options in Telerik Reporting Q1 2013? You can get them from your account.