Creating Invisible signature in Excel documents

Question

Using a DocuSign Signature Appliance (CoSign), I am trying to sign office/pdf documents. Well the signature has to be invisible. It works with docx and pdf documents but does not work for xlsx documents.

I don't understandy why..

I am following that document

https://www.arx.com/forum/content.php?131-Sign-PDF-File

I tried many combination of

SFS.Invisible = 1;
 SFS.Page = -1;

but no way..

Is there any special thing for excel documents to sign invisibly?

Answer 1

This function has been solved my problem. It works for pdf, docx, xlsx to make invisible signature

 public const int AR_MS_SIGNATURE_LINE_ONLY = 0x00000001;


 SignatureFieldCreateSignEx(SesHandle, fileType, fileName, SFS, AR_MS_SIGNATURE_LINE_ONLY, null);