Duplex (2 sided printing) Problem

I have two different types of printers that support Duplex printing: Brother HL-2270DW and a Cannon MX-510.

When I open up the print dialogue box under some programs (Firefox, Microsoft Outlook, Safari) the print dialogue box has a check box for "Two-Sided" printing. When checked, the printers will print out on two sides.

Under other programs, (Word, Excel, Adobe Acrobat) a different type of print dialogue box opens without a "Two-Sided" box option. I checked the various drop down boxes within the print dialogue box, and none seem to allow for two sided printing.

My question, how can I get two sided printing under Word, Excel & Adobe Acrobat?

The printers work fine when offered the option of two sided printing, so I don't think it's a printing problem.

I get the same print dialogue box under Word, Excel or Adobe Acrobat, so I don't think it's a program issue.

Any suggestions?