From a Word 2008 for Mac file, after creating PDF with hyperlinks, how do I preserve the ScreenTips

ScreenTip allows hyperlink text to provide a meaningful description of the link destination (i.e., a name or phrase), instead of only the URL. The link text includes a ScreenTip (text similar to alt text that appears when you point your cursor over the link) and matches the link destination.

Am unsure why the PDF has not preserved this function. Can I add it in?