This is probably stupid, but.... when you say skin2 in MED do you mean when you add another skin under the "veiw skins" tab and select "add after last skin" or is there actually a "skin2" checkbox somewhere that I just have not seen. Other wise I was just trying to add it to code like this:

bmap box = <box1.tga>;

material spec_bump_model //assaign all models this material in script
{
skin2 = box;
flags = tangent;
}

I still get a black model though . Also, do I need an alpha channel or can I just have a regular skin and a normal map? I tried this and saw no change to the model. Not black, but also no bumpmap.