Symptoms
Preview documents from SharePoint site into a form in K2.
Diagnoses
Instruction needed to use the Save as PDF control to configure document preview.
Resolution
The following will provide information on how to use the Save As PDF control and how to integrate with SmartForms. You will need to do some integration with SmartObjects and this documentation will help you achieve your goal.
http://help.k2.com/onlinehelp/k2smartforms/userguide/current/default.htm#pdf_control.html