Well maybe the units don't work with the zweihander soldier model. I have no experience in that area, either unfortunately so I can't tell you anything about it.

Musashi: I figured out the problem is that the game needs certain files to recognize other files, for example to use the files in /text you apparently need the filter.san and filter.san.chk files. So that's one more thing you have to figure out if you don't want to have users of your mod completely unpack their packs...
Anyhow, the command line option is the exact equivalent of a boolean ini setting afaict, and that was one of the first things I tried ;)