Where is digital signature on forms users submit with the "Submit by Email" button?

I created a form in Adobe Livecycle 9 that contains a digital signature field and a submit by email button and then I enabled extended Reader features for the form using Adobe Acrobat 9.

End users download the form from our website and fill it out with Adobe Reader 9, signing it digitally, and submit the form to our mailbox with a Submit by Email button. When I receive the data file, I import the form data into the blank form using Adobe Acrobat 9.

Here's the problem. the digital signature doesn't appear when I import the form data. All the other fields appear but that doesn't do me much good if I can't see any evidence of a signature. Is the signature info captured somehow else in the data document? How can I see it?

This sounds like it should be a simple question and answer but I haven't found the answer either with a Google search or by a search on these forums.