ToiletFreak did you read the tutorials on rigging your character?
because you have to follow those steps TO THE LETTER to be able to export 3DS - you can't simply attach the modifier, you have to take the long route i'm afraid.
Remember that 3DS - DO NOT USE MESH DEFORMATION, you will HAVE to setup and export as linked objects.
you want to see a simple way of what i mean, make 2 cubes ... use the chain w/box icon and click from the original box to the second box.
now set the base keyframe - and then move one of the boxes like rotate it, then set the keyframe.
now export and you'll notice that 3DS now has that animation.
how the effect of the bone animation is no different, all you have to do is setup the exclusive/inexclusive envelopes for affecting the limbs in the same way - and you must make sure you chain link in the hierachy order of the bones (because else they'll all appear on the spot when exportered)
now you'll notice they'll export with the animation properly
and don't worry about having the animation the right amount of keyframes, just make sure you have the right distance of keyframes for the animation to work (say you have 12 keyframes, place them only 1 frame apart with the exception of the subtle movement keyframes ... this is because keyframes are not only space intensive, but moreover they're automatically interpolled within DirectX and you can find that for some reason you're actually exporting several thousand frames even though you only have 30frames lasting 1second (its weird but its how max works)
you can setup the interpol ingame if you need to
Tsu'va Oni Ni Jyuuko Fiori Sei Tau!
One block follows the suit ... the whole suit of blocks is the path ... what have you found?