Fellow Palmtopper Rodolfo provided information about his efforts to fix a broken keyboard. THANKS for sharing!
I´m going to try to describe in my poor english exactly what i did. Unfortunately I don't have pictures for the whole process. What it happened was that I previously (I did not know how to do it) use cyanoacrylate super glues to stick on graphite in powder in every bubble of the keyboard, where I saw it was an erosion marks. Well, that was a big mistake because the blend (which got hard after drying) was to thick and irregular, and when the keyboard was assembled some of the keys did not move at all, and others did not make contact. When I tried to clean it up with isopropyl alcohol, it didn't work. Then I thought that the keyboard was destroyed because that glue agent is extraordinarily strong and every spot was hard.
Next day, I decided to use a mini drill with a spherical stone. I used it very gently in every spot (concave parat of bubble) and when I finished the whole part was completely transparent. Then I bought Graphite paint for re-paint remote controls contacts and with a cotton swab (for inner ear) I stamped (painted) the graphite pain spots, I painted three coats in every bubble (you have to wait half an hour between coats), and the result was perfect.
To repair two keys (the top part with the keys you press to type) they have one of the two supports to the frame that has every key were broken, and I used the same cyanoacrylate super glues to glue them to the frame.