Cannot do Certifying signature inside an AICapp displaying Acrobat

[Jim_Lomax@adobeforums.com]

I have a Windows VB.Net application that displays a PDF file in an embedded Acrobat Control. The PDF has several signature fields with the top one set to do a Certifying signature. This configuration is done using JavaScript earlier in the workflow then the PDF is saved to a temporary file. If I copy the temporary file (the original gets deleted automatically) I can open it in freestanding Acrobat (9 Pro) and can sign the certifying signature with no problem. But within the application when i click on that field nothing happens.
I have just downloaded the SDK and run the AcrobatActiveXVB sample and when I load my saved file in there I see just the same problem - unable to do a certiying signature.
Can anyone help work out what is happening here?

Since it happens with the Acrobat 9 SDK sample, my specific versions and controls used are not so relevant (I am of course using Acrobat Pro 9). I can supply the PDF file if that would help.

Thanks.

[Leonard_Rosenthol@adobeforums.com]

The "embedded Acrobat control" does not support the operation of applying a certifying signature.