Zero button for tripometer & Rocker panels

[afflora]

Where is the zero button for the Tripometer (SP) on a 77 Spider 2000 I would like to zero it out after every fill up. Can any one help?
Slowly getting it to a point where I will be comfortable with my son driving it. However, he has to get the grades up otherwise it is Dad's car!!!! Also can someone explain to me the rocker panels - where they are and what has to be done if they need replacing. I will have to redo the floor panels on the driver and passenger sides at some time but that is for further down the road. I guess a cutting torch and welding rig will be needed then.
Thanks

[Roadtrip]

The tripmeter reset knob goes through a short cable from the Speedo to the bottom of the instrument panel. Push and twist to reset.

The rocker panels are below the doors. There are three:

1. Outer Rocker (what you see and is painted). Not structural
2. Middle sill
3. Inner sill (Structural)

New metal for outers is available and a good body man can weld and blend them in pretty easily. The inners are structural, and along with the flooring, literally connect the front and back half of the car, since it's a convertible. Badly corroded inner rockers are very expensive to replace. Unless the car was relatively rare (old Duetto), it's probably not worth it to pay someone for. As a '77, as a practical matter, rusted out inner rockers would probably relegate the car to a parts donor, especially since the rest of the car probably matches the rockers in corrosion and wear.

Do a search on the BB. Lots of previous discussions on rockers.

See this link for a cross section of a Spider sill.

http://www.alfaparts.net/105_115sill.htm