It's been a while since worked on leaderheads with 3ds max. When I did last time, I had no luck to get the plugin your are using working for export. I mean, you definately need it for import, but when using it for exporting, I got nothing working. Instead, there is another plugin used for export. Search for a tutorial written by ploeperpengel, here in the tutorial section. There you'll see how you can export with 3ds max properly. The only problem is, that the plugin I am speaking about, works only for 3dsmax 7 and 8 (maybe 6). AFAIK there is still a thread for 'my' plugin in the c&c main forum (you know, where people are supposed to ask questions if there is no tutorial about their topic available).
Also, I noticed that Ekmek does a different nifswap then I do. At least, I think so. I think Ekmek swaps some nodes, too, while I am only swapping meshes. Do it the way described in ploeperpengels tutorial.
Note: when working on units, your plugin might be okay.