Can't load top feeder to scan multiple pg's from Sharp AL-1655CS

I use Adobe Acrobat Professional 8 and my Printer/Copier/Scanner is a Sharp AL-1655CS. It will scan doc's to pdf's if I place them face-down on the glass one at a time. However I need to scan multiple pg's loaded from the top feeder. I can't see any settings that would let me use the top feeder. Any ideas?

 

Copiers with which I am familiar require you to put the documents in the feeder, select Scan and press Start. No other settings.