Algorithm - shader, normal, tangent, bitangent?

Hi

I searched through the Archives and posts on the forum but I can find what I looking for. Has anybody got any pointers on where I might find some algorithms to calculate some byte based normal, tangent and bitangent (binormal) values. I need it for a converter that is being written for Medieval Total war2, to convert their mesh files to and from MS3D.

I tried Google but I could not find much there either.

Thanks for any help

Cheers

GrumpyOldMan