Change Volume using External keyboard with Macbook?
You could try using a private.xml like this with KeyRemap4MacBook:

&lt;?xml version="1.0"?&gt;
&lt;root&gt;
  &lt;item&gt;
    &lt;name&gt;test&lt;/name&gt;
    &lt;identifier&gt;test&lt;/identifier&gt;
    &lt;autogen&gt;__KeyToKey__ KeyCode::F1, VK_CONTROL, KeyCode::BRIGHTNESS_DOWN&lt;/autogen&gt;
    &lt;autogen&gt;__KeyToKey__ KeyCode::F2, VK_CONTROL, KeyCode::BRIGHTNESS_UP&lt;/autogen&gt;
    &lt;autogen&gt;__KeyToKey__ KeyCode::F3, VK_CONTROL, KeyCode::EXPOSE_ALL&lt;/autogen&gt;
    &lt;autogen&gt;__KeyToKey__ KeyCode::F4, VK_CONTROL, KeyCode::LAUNCHPAD&lt;/autogen&gt;
    &lt;autogen&gt;__ConsumerToKey__ KeyCode::F5, VK_CONTROL, ConsumerKeyCode::KEYBOARDLIGHT_LOW&lt;/autogen&gt;
    &lt;autogen&gt;__ConsumerToKey__ KeyCode::F6, VK_CONTROL, ConsumerKeyCode::KEYBOARDLIGHT_HIGH&lt;/autogen&gt;
    &lt;autogen&gt;__ConsumerToKey__ KeyCode::F7, VK_CONTROL, ConsumerKeyCode::MUSIC_PREV&lt;/autogen&gt;
    &lt;autogen&gt;__ConsumerToKey__ KeyCode::F8, VK_CONTROL, ConsumerKeyCode::MUSIC_PLAY&lt;/autogen&gt;
    &lt;autogen&gt;__ConsumerToKey__ KeyCode::F9, VK_CONTROL, ConsumerKeyCode::MUSIC_NEXT&lt;/autogen&gt;
    &lt;autogen&gt;__ConsumerToKey__ KeyCode::F10, VK_CONTROL, ConsumerKeyCode::VOLUME_MUTE&lt;/autogen&gt;
    &lt;autogen&gt;__ConsumerToKey__ KeyCode::F11, VK_CONTROL, ConsumerKeyCode::VOLUME_DOWN, ModifierFlag::OPTION_L | ModifierFlag::SHIFT_L&lt;/autogen&gt;
    &lt;autogen&gt;__ConsumerToKey__ KeyCode::F12, VK_CONTROL, ConsumerKeyCode::VOLUME_UP, ModifierFlag::OPTION_L | ModifierFlag::SHIFT_L&lt;/autogen&gt;
  &lt;/item&gt;
&lt;/root&gt;


I don't know if it works with all keyboards, but it does work with my Kinesis Advantage.

See http://lri.me/keyremap4macbook.html for more information about using KeyRemap4MacBook.