As I was installing ESXi v5 in my lab I came across a prompt to press F11 to accept the license agreement, that I fully read :). On my Mac I was using iDRAC v6 Enterprise via the browser to install the ISO image. When I went to press F11, my Mac’s desktop was shown. I have the full Apple USB keyboard so I tried using the fn key with F11 and without, each time with no success. I thought I’d start in the System Preferences section under Keyboard. Under the Mission Control section there was a short-cut for F11 and F12 that was grabbing the keystroke before it was sent through the browser.
Once I un-checked the “Show Desktop” and “Show Dashboard” I was able to reply to the license agreement prompt with F11.