Send fax to right fax server using .net fax object not able to send cover sheet notes

Question

oFax = mRightFaxComServer.Faxes[faxFileInfo.RightFaxSettings.RightFaxServerObject].Create; 
        oFax.OwnerID = faxFileInfo.RightFaxSettings.OwnerId; 
        oFax.ToName = recipientDetails.RecipientName; 
        oFax.ToFaxNumber = recipientDetails.FaxNumber; 
        oFax.FromName = recipientDetails.SenderName; 
        oFax.Attachments.Add(fileName); 
        oFax.NeedsPDFConversion = true; 
        oFax.isFineMode = true; 
        oFax.NeedsPreScan = true; 
        oFax.CoverSheetNotes[1] = recipientDetails.Notes; 

These lines added to send cover sheet notes but we are not able to see notes population on cover sheet. Above code works for version 9.6 as expected