Santi,
The Office Help on the AttachCertificate Property only mentions Word and it
does not appear that Excel has a corresponding Signatures collection.
In Excel (2002 anyway), you cannot sign the workbook, only the VBA code,
which you cannot access by code AFAIK.

Also, the Help is somewhat confusing on this, indicating it for emails
signatures and digital signatures, which are 2 unrelated aspect, to me.
<From Help
Add method as it applies to the SignatureSet object.
Returns a Signature object that represents a new e-mail signature.
</From Help
I suppose this what appears in the WordOptionsGeneralEmail OptionsEmail
Signature

And also

<From Help
SignatureSet Collection
A collection of Signature objects that correspond to the digital signatures
attached to a document.
</From Help
Not sure what this is supposed to represent in Word.

The only related object in Excel is the VBASigned Property:

<From Help
True if the Visual Basic for Applications project for the specified workbook
has been digitally signed. Read-only Boolean.

</From Help

Good luck, but I don't think you can achieve your aim, although it is highly
likely I'm missing something.

NickHK

"Tom Ogilvy" wrote in message
...
Are you sure it isn't signatureset rather than signature?

--
Regards,
Tom Ogilvy


"Santi" wrote:

Hi,
I am looking for information to apply digital signatures to a
..xls
document from VB. I saw how to do it in a Word document:

Set wordapp = CreateObject("Word.Application")
Set worddoc = wordapp.Documents.Open(docu)
wordapp.Visible = True
Set sig = worddoc.Signatures.Add

In Excel it must be similar using Excel objects instead of Word, but it
fails. Can anybody help me?

Thanks