How to replace the keyboard on this Ultrabook

I am about to pick one of these up in which the guy claimed that it had a bad keyboard (only some keys work)

I am getting it heavily discounted, but looking at the pictures I noticed it isn't like the other Vaios; it's keyboard is its own piece not just built into the top of the laptop, but placed underneath the Bezel(?).

The keyboard basically looks like one on a macbook where only the keys are exposed and are separated by the case.

How hard is this to replaced