membrane switch repair,need help.

[droopy]

Dear all;
I have a instrument,It has a membrane keyboard.
some of the key have broken out.

I need to replace the keys or build a new keyboard.

1)firstly ,is it possible to change keys?
It seems the key was polymer or something.

2)If I can't replace keys;
I hope I can replace the keyboard with some keyboard?

So,I think first I need to identified every key how to link to the I/O
port,I need your advice here.

and could I find a standard keyboard which can define every keys?

very thanks