You can use RadUpload with WCF Ria Services. You need to use the uploaded files on the Server so I think this KB project would be useful in your scenario. As for the documentation, the "UploadHanlder" help page is located in the Features section. You may also find different tips and trick regarding the UploadHandler in the "How To" section.
Feel free to ask if you need further assistance.
the Telerik team
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