After searching and searching, I found a solution. I took this from the following link, I will quote it here:
http://forums.macrumors.com/showthread.php?t=1073018
This works on 10.8 as well.
"What you will need:
KeyRemap4Macbook - Works for Lion, Snow Leopard, Leopard, and Tiger.
Steps:
1. Download and install KeyRemap4Macbook. Restart is required for use.
2. Open System Preferences > KeyRepma4Macbook
3. Make sure you are on the "Change Key" menu and click in the search bar in KeyRemap4Macbook, not the search for System Preferences.
4. Type "eject" in the search bar and check the box next to "Eject to Command+Control+Option+Shift+E"
5. Exit System Preferences and open Automator.
6. Choose the template "Service" and hit "Choose" at the bottom right.
7. In the search bar at the top left, type "Run Shell Script"
8. Drag "Run Shell Script" from the left to the Workflow Area.
9. At the top above "Run Shell Script" click the arrows next to "Service receives selected text" and pick "no input" at the bottom of the list.
10. Next delete "cat" from the Shell Script and type this "drutil eject"
11. While in Automator go File > Save As > Eject
12. Close Automator and open System Preference > Keyboard > Keyboard Shortcuts
13. In Keyboard Shortcuts choose Services in the left box.
14. In the right, scroll down to "General" and you should see "Eject" listed.
15. Make sure the box beside "Eject" is marked and double click on the right side just to the left of the scroll bar.
16. This should bring up a textbox, in this box type "Command+Control+Option+Shift+E"
17. After you do that it should close the box and you will then see the key combination listed beside "Eject"
18. Close System Preferences and the Eject key should now eject your external cd/dvd drive."