Alas, it works, but within AC3D only!
In the exported files (all formats I tried so far) the materials were still named "
acmat0, 1, 2...".
Still worse, once materials are renamed those nefarious "
acmatX" disappear entirely from the .ac file, thus there seems to be no easy way to build a cross-reference table automatically - unless the exporters number the mats progressively after their order in the .ac file; in that case contriving a simple prog to build the x-ref table and rename them in the .obj shouldn't really take long.
As soon as I can (right now I'm expected to take care of my boring Monday stuff) I'm going to check that last possibility and let you know.