How can I add additional drivers on Windows Server 2012?

I just set up a print server on a Windows Server 2012 Standard machine.  I have all of my printers set up and they are working properly.  The only problem is that I can figure out how to add a 32 bit driver to one of the printers.  When I go to the "sharing" tab, the "additional drivers" button at the bottom is greyed out. 

I was able to add a driver under the "Drivers" section of the Print Management snap, but I can't figure out how to get the 32 bit driver associated with the printer.

Nate