Detecting a present signature in a Word 2007 document using VSTO

I'm trying to detect a present signature in a Word document with VSTO. I am stuck, because one I don't have much experience with VSTO and second I can't find any documenta开发者_运维问答tion about this.

What did I develop so far?

1. Created a Ribbon Add-In for Word 2007, with two buttons.
2. Created methods for handling the clicked buttons.
3. When Start Debugging, Word opens with a document which include a Signature Line(locally stored document).

Where did I get stuck?

I've tried to figure out which properties are involved with Signature. Some code:

Word.Application wa = this.applicationObject;
Word.Document doc   = wa.ActiveDocument;
SignatureSet ss     = doc.Signatures;

As a result the SignatureSet remains empty, while there is a present Signature Line. The count property is always 0.

What should be fixed or done to get a working IsDocumentSigned Method?

All kind of tips and tricks are pleased to see :)

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I think Farrell found an answer for this question on the MSDN forums, here is the link if anyone is interested.

http://social.msdn.microsoft.com/Forums/en-US/vsto/thread/f032a616-ee63-424b-b56d-1e495e241b0e