The PDF to be signed that I originally created using Adobe Acrobat software included an Excel file in xlsx format that was added through the attachment function in Adobe Acrobat. However, after uploading the sign webpage for signature action, the attachments included in the file disappeared. Since the files we provide are in the original Excel format and require proof that they have not been modified, but the current design of sign is that sign will perform a Flattening process on the uploaded PDF files, and Flattening will strip the attachments from the PDF files. Therefore, sign's current functionality cannot meet our business needs. Please assist in updating sign. Thank you.