Trip Meter

[3-D Video]

I've got a problem resetting my trip meter. The knob, plunger, doohicky thing-a-majig is missing. I don't have the speedo in front of me to play with, but I'd like to have every thing I need to fix it when I do (in a week or so)… it's about 2500km south of here.
I guess the big questions are, does it turn to reset? Push or pull to reset? Is it metal, plastic, or bamboo?

Thanks