Also, if your model comes out screwy, there is another way to do this without any sort of special plugins or anything for 3ds max. It is a very time consuming process if you have a lot of animation frames, but the finished result is very high quality; can't export bones this way I think.
The whole process involves having a static version of the model in .MDL format before hand. The idea is to export a model in .3DS format, import it into 3ds max, rig it, animate it, etc...
If you have a model in .MDL format, go ahead and delete all frames of animation in MED (if any, and don't forget to make back up saves), then export it to .3DS format. Next, import the model in 3ds max and do all of your rigging and animation.
Next, make sure to select the objects that you want to export, and export them to .3DS *from* 3ds max frame by frame.
Import the frames one at a time in MED using "Append Frame...", make sure to clean everything up before using the model.
Also, I would like to point out that when you import the model frame by frame in MED, the appended frames use the same skin mapping, nothing has ever been screwed up there.
P.S. If you don't have the patience, don't use this method.
