Okay...
I found the _lgt versions, which have beautiful black & white shadows.
I just let bc42 merge the shadows, and found two very slight problems.
1) The shadows are looking
towards the sun. Naturally this would look strange ingame. But that's nothing, because
2) They're completely red!
I thought I had f-d up the shadowcolor in my map, so here's what I did:
1) made a new medium-sized map in bc42
2) saved it,
3) extracted it
4) added my textures into it
5) packed it
6) put the textures & new _lgt.tga's into the level folder (new correctly named folder ofcourse) in the shadowworks folder
7) opened the map in bc42
8) set the shadowcolor to a proper slightly red gray
9) created shadows (lowest quality, no heigthdata for the map)
10) replaced the new _lgt.tga's with my proper _lgt.tga's
11) merged lightmaps
And they're
still covered with a bright red overtone:

The sun is located in the bottom right corner compared to this image.
I'm about to call it quits for shadows alltogether, someone
please give me true & working step-by-step instructions. No need to use noob-lingo, but just what to click, or what setting to set, or what?
EDIT: Come to think of it, is there some fancy way to merge them in Photo- or Paintshop? Open the etxture.tga, create a new shadowcoloured layer, and use the _lgt.tga's as the alpha channel for that layer. That would mean just regenerating the shadows with the proper sun (ie completely other way around)