what I have figured out is that you can not append 3ds models for some reason, I cant anyway.
so I always have the main model (with idle animation) saved in a 3ds (to save space) and the rest of the animations (walk, run, die etc.) in a directX file.
then to append it you need to know how many frames each animation has. (mine is always on 25 frames) but if you dont know, there is a command in dbc that can give it to you. (I think it is [url=file://localhost/c:/program files/dark basic software/dark basic/help/basic3d/ototal.htm]
Total Object Frames()[/url])