I've found a discussion that puts an existing PDF file as the icon for a button on a form. But I cannot find steps to do so. What I want to do is create a hidden button that contains an "Instructions" document as it's "caption" or "Icon" that will be revealed when the user of the form wants to see instructions.
http://forums.adobe.com/message/2386742
This solution may not apply to LiveCycle, but it would be nice.
Thanks in advance