Well... not so easy as I intend to present, but I encourage everyone to do.
All Brazilian 79 models have a wood adhesive over the panel. Since I was a child I dreamed with a wood panel in my car. So I decided to buy a wood sheet and cut it. First I draw in Corel draw a panel masked, tested if it fits and them, I finally cut it (past sentence...) using a blade.
I painted it with a thin layer of varnish and tried to polish.
I also repaired the hole in the original stereo place. I welded plastic pieces. It is pretty easy to do. Use a scrap plastic piece, heat it with a weld gun. To enforce it I made a layer using epoxy glue plus fiber.