How to active F16 function key?

I have a MacPro with a wireless keyboard that has F1-F16 function keys. I cannot figure out how to activate them; I am trying to emulate the Pause/Break key on a PC, which is F16 on a Mac. System Preferences, Keyboards doesn't give an option to activate the function keys. Some instructions I've found for other keyboards say to hold down the function key (Fn) while pressing the desired function key, in my case F16. But there is no function key on this keyboard.

So, how do I activate the F16 function key to make it act as a PC Pause/Break key? Thanks!!