Hi James
Strictly speaking, you can't. The Workflow system has its own mechanism for handling attachments - they are attached via Form Manager's custom "attachment" user interface, rather than being attached "inside" the PDF.
You could get at these attachments, and attach them to your outbound email as regular attachments, rather than embedded within the PDF.
If you have a strong requirement to embed the attachments inside the PDF, there may be something we could do. Please email info-at-avoka.com if you want to discuss further.
Howard
http://www.avoka.com