Thank you for sharing this with the community.
You are right the RadAsyncUpload will move uploaded files on postback, but this can be changed. It is possible to read and save the file stream manually. Also you can change the Temporary Folder to a folder that your FTP user has permissions. AsyncUpload has a UseApplicationPoolImpersonation
, which defines whether to use application pool impersonation.
The problem is confrontational and cannot resolve it.
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