O-Gauge Walthers Passenger Cars?

Gentlemen,
I'm building a few O-Gauge Walthers Passenger Car - Hiawatha. I'm looking to get some part for them. I was told Keil-Line is one company which bought out Walther's O-gauge parts but I still can't find some items.
I'm looking for replacement windows,
Also I was told that Walthers had made a retrofit kit which I can add to the underneath of the roof so I can open and close the car as many times as I want to if I want to add details later.
Please if someone know of them. Or any valuable information that they can give me it will be much appreciated.
Thank you

You can find it on EEEEEEE-Bay, my brother is accumulating Walthers "O" Hi car kits and has had good luck in the "Other" section under O-Scale finding various parts for this very good series. Keil-line has(had?) stuck largely to the more generic heavyweight parts to repro, though it wouldn't hurt to drop him a line though last I checked he was still snail mail only. Good Luck!

Oh yeah, RE the roof mounting kits, with Walthers psgr. car kits I skip those and prefer a single #6-32 x 2" machine screw and nut set at the absolute center of the car. The Walthers mount kits I used consisted of smaller diameter but equal length brass screws that were mounted at the corners. I secure the nut to the roof with a short plate over a submerged mounting hole on the underside on both wood and cast epoxy stock, I also use the same method on ALC and ICC plastic kits by shape-sanding a wood insert with the nut embeded and then cement the whole deal into the roof. The centered screw pulls all sides down evenly and eliminates the "warp-edge" I'd get with the Walthers rig. For me cheaper, easier and better result.