you can use Character Studio with DBC, you've just got to be tricky, because DBC doesnt automatically support mesh deformations.
"Easy" Way: Constraints.
With a regular segmented model that you would use for DBC. You have to use position and rotation constraints for each peice and constrain them to the respective biped part. Animate the biped, then collapse the constraints on the peices back into standard keyframes for your character objects. And then you can export as a 3ds or .x with all the keyframes.
Hard Way: Mesh Deformations
The other way is to use mesh deformations. But to do this you will have to more or less make a custom 3D file format for DBC.
First make your character, then rig it using Biped/Physique or Bones/Skin and animate it. Then you need to make a quick maxscript that will export .3ds files for each frame of the animation.
Then you need to fire up DBC and write a program to take all the individual frames of .3ds files, and basically rip out all the vertex location data out of each one. Then save that data in a special format all in one file.
Then you can use memblocks and CHANGE MESH FROM MEMBLOCK command to update the mesh frame by frame.
Either way its a lot of work, but its possible...