I have created a linked document and set it to print as a Link on the Acknowledgement.  Whenever I print the sales order acknowledgement, nothing happens other than I get the ack. but not the linked doc.  I can click the camera icon in the SO and the doc loads.  It is a Word document.
 
Is there something special that needs to be done to get the link to launch whenever the acknowledgement is printed?  The help file is anemic and un-helpful regarding any specifics on how to setup linked documents (it only tells you the feature exists).
 
Thanks!