I think the plug that John is referring to is this one from Radio Shack , although this one may also work.

As for the connections, the wire from the narrow blade on the extension cord (the hot) goes to the tip of the mini plug (based on Jedi Mike's info above). The mini plug should have two places to connect to -- one for the tip and one for the body. I'm guessing that once you get your hands on one of the mini plugs, the connection that goes to the tip will be the "smaller extension side of the plug" but I'm in the same boat as you, having not actually put eyes on one.

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