When using the wpf RadCloudUpload, you need to implement your own Provider that handles the actual file upload (as explained in the online documentation here http://www.telerik.com/help/wpf/radcloudupload-features-providers.html). We do not offer out-of-the-box support for any cloud storage provider, and you need to implement a custom class for each storage drive you need. 

This being the case, I have to deny the feature request and suggest that you use the ICloudUploadProvider interface and create your own file uploader. You will find some sdk samples here (https://github.com/telerik/xaml-sdk/tree/master/CloudUpload) that demonstrate one way to get this done for Azure, Amazon and TelerikBackendServices.