Its the terrain that is black? Somehow I believe the way BfME2 handles terrain is different to the way BfME1 does terrain. So whenever I've tried the same thing as you I've got a completely black map that I would have had to repaint.
Yes it's the terrain and I think you're right, WB2 seems to deal differently with terrain. Later, I repainted the whole map and I got a pinkish terrain in game (with the right textures underneath) as if a texture was missing.
Anyway, thanks for your answer.
(My ambitious goal is to import BFME2's campaign maps into BFME1's campaign, which I think represents a "huge" amount of work but is clearly possible with robnkarla's new living map and NDC's converted animations).