Map "Play" button to keys on keyboard?

Hello all!
I am wanting to be able to map the Play button on the timeline to either the Enter key (like Flash) or the Spacebar if possible. I’d actually take the ability to map it to any key but I can’t find the function in the Shortcuts Prefs… Am I missing something? Is it not possible?

The default for “Toggle Playback” is shift-return…
Space might be already taken by another shortcut key…
If you insist, either Duplicate or Replace your choice…

In the Preferences Panel / Shortcuts / General select Toggle Playback.
Press the keyboard-button (left of the “Clear” button).
Press your chosen key/s on your keyboard.
click OK.