What I do is place the cursor where I want to duplicate the footnote and add a superscript. Choose format>font>baseline>superscript (you can also customize the pages tool bar to add the super/sub script buttons by control clicking on the toolbar and choosing 'customize toolbar')
The problem with this is that in the document, the superscript is not linked to the footnote. While in the Pages document if you double click on a footnote in the text you will be taken to the bottom of the page to the footnote. But if you are just printing out the document this should not mater.