Question : Adding a signature to a PDF programmatically with Acrobat 8 (Reader 9 validation issue)

Question

Hi,
Please, apologyze my poor english.
I have an application that inserts a signature programmatically in a PDF document with Acrobat 8, via VB .NET, using the example provided in the Acrobat 8 SDK ("AddSignature").
The problem resides in that previous signatures in the document (signed normally via reader 8 or acrobat 8 application), now becomes INVALID, but only in Reader 9.Acrobat 8/Reader 8 considers them as "valid, with posterior changes".
The difference between the SDK example and this code resides only in the way of calling the script in .net
I call directly the AddSignature function with this code (partial), instead of calling the execution of the "ADBESDK:AddSignature" menu (this improves faster execution with no AVDOC object involved):
        AcroExchPDDoc = New Acrobat.AcroPDDoc
        Dim JsObj As New Object
        AcroExchPDDoc.Open("c:\test.pdf")
        JsObj = AcroExchPDDoc.GetJSObject
        JsObj.SetUserDigitalIDPath("/C/trabajo/DrTest.pfx")
        JsObj.SetUserPassword("testpassword")
        JsObj.AddSignature(JsObj)
        JsOb = Nothing
        AcroExchPDDoc.Save(1, "c:\result_test.pdf")
        AcroExchPDDoc.Close()
I tried to change the AcroExchPDDoc.Save() parameters for intend an incremental save instead of a fullsave, but i keep getting this situtation.
How can this be solved?? Is this a bad approach to the process??
Note that all inserted signatures trough this method are valid in Reader 9.
Any help or comment would be appreciated.
Thanks.

Answer 1

Thanks Steven,
There is something I can´t undestarnd about this issue, and hope you can throw some light on it...
If I use the AddSignature method of Adobe 8 SDK by clicking on the new menu option that it creates, these inserted signatures not causes the invalidation message in Reader 9. The used script is the same, so I can´t figure out why.
Once inserted a new signature by ("my") code, it invalidates all previous "normally" inserted signatures trough the GUI, but not invalidate other signatures inserted trough this code (No matter how many signatures of this type are present in the document).
        I suppose that this means only a blank outline tree is inserted, and only the first time I apply the signature.
As an additional info, I´ve attached to this post a new pdf file with one signature normally inserted, and three signatures "code-inserted". (The "result_pdf.pdf" included in previous post, with another two code-signature).
As you can see, all except the first are valid, and any other new signatures inserted in the document (normal or code) won´t result in an invalid statement after the 1st code-insertion.