Rear brake problem on 93 90Q

[Gabor Jacques <neotek@virgin.net>]

Two weeks ago I replaced the rear brake discs/ rotors and pads as the
old rotors were badly scored and corroded and not providing much braking
force. I have noticed that the pads are only gripping on the outside
half of the rotors, the inside half are beginning to show signs of rust
appearing and are not bright and clean like the outside. The handbrake
does not hold the car on a hill very well either.
Can anyone advise as to what the problem here is?  Could this be a sign
of seized calipers?

Regards
Gabor