Hello Rick,
I have examined the file and this is not supported. We have a feature request for it on our feedback portal. You can track its progress, subscribe to status changes, and add your comment to it here: PdfProcessing: Add support for Stamp annotation.
I have linked both items. I cannot say when we will be able to implement this.
I want to apologize for the inconvenience this is causing you.
Regards,
Dimitar
Progress Telerik
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