On the first generation vibes, there is a thin black plastic cover that is held in place on each side by a plastic rivet type body fastener. I think you are looking for that fastener.
If you want the exact part, it's Toyota part number 90467-07071-22. You could probably stop by a toyota dealer's parts department and buy/order them, or buy them online. Online, a lot of places sell them in packs of 25, but one place you can buy individual ones is
http://www.toyotapart.com/90467-07071-22.html" onclick="window.open(this.href);return false;
I think the way to remove those to access the light bulb is to either pry the center piece out, or perhaps push it in all the way. Trying to remove the entire fastener with the center pin in place will be trouble. Its another of those things about working on cars. You'll read some step by step instructions, it will say something like "remove the cover" or "unplug the connector" and it will take an hour to figure out the secret release mechanism
Weird that something in Reynoma's signature threw the thread into bold italics. Happens in other threads he posted to also. Haven't seen him here for a long time