Is there a sane way to emulate the newer media key behavior completely on an Apple Extended Keyboard II?
You could try KeyRemap4MacBook:

or FunctionFlip:

If neither works, you could also try creating a private.xml in KeyRemap4MacBook:
&lt;?xml version=&quot;1.0&quot;?&gt;
&lt;root&gt;
&lt;item&gt;
&lt;name&gt;Change F-keys&lt;/name&gt;
&lt;identifier&gt;0A0FE074-9C9C-43DC-8AEB-6683C5CB3259&lt;/identifier&gt;
&lt;autogen&gt;--KeyToKey-- KeyCode::F1, KeyCode::BRIGHTNESS_DOWN&lt;/autogen&gt;
&lt;autogen&gt;--KeyToKey-- KeyCode::F2, KeyCode::BRIGHTNESS_UP&lt;/autogen&gt;
&lt;autogen&gt;--KeyToKey-- KeyCode::F3, KeyCode::MISSION_CONTROL&lt;/autogen&gt;
&lt;autogen&gt;--KeyToKey-- KeyCode::F4, KeyCode::LAUNCHPAD&lt;/autogen&gt;
&lt;autogen&gt;--KeyToConsumer-- KeyCode::F5, ConsumerKeyCode::KEYBOARDLIGHT_LOW&lt;/autogen&gt;
&lt;autogen&gt;--KeyToConsumer-- KeyCode::F6, ConsumerKeyCode::KEYBOARDLIGHT_HIGH&lt;/autogen&gt;
&lt;autogen&gt;--KeyToConsumer-- KeyCode::F7, ConsumerKeyCode::MUSIC_PREV&lt;/autogen&gt;
&lt;autogen&gt;--KeyToConsumer-- KeyCode::F8, ConsumerKeyCode::MUSIC_PLAY&lt;/autogen&gt;
&lt;autogen&gt;--KeyToConsumer-- KeyCode::F9, ConsumerKeyCode::MUSIC_NEXT&lt;/autogen&gt;
&lt;autogen&gt;--KeyToConsumer-- KeyCode::F10, ConsumerKeyCode::VOLUME_MUTE&lt;/autogen&gt;
&lt;autogen&gt;--KeyToConsumer-- KeyCode::F11, ConsumerKeyCode::VOLUME_DOWN&lt;/autogen&gt;
&lt;autogen&gt;--KeyToConsumer-- KeyCode::F12, ConsumerKeyCode::VOLUME_UP&lt;/autogen&gt;
&lt;/item&gt;
&lt;/root&gt;

It might only work if you use the external keyboard with a laptop or have another keyboard connected. From ConsumerKeyCode ignored - Google Groups:

KeyRemap4MacBook requires at least one keyboard with functional keys (Volume Control, etc)
when you want to change keys to functional keys.
If possible, please connect the Apple keyboard to iMac.
If you don't have another keyboard,
please use Spark or Quicksilver or other apps to this purpose.