Putting a PDF document in a button

[kammsba]

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