As far as I know, *.bip-files can be importet into character-studio.
CS is an add-on for 3dsMAX that offers a fully jointed and customisable biped as a template for character animation.
You can scale each bone of this biped until it fits your model and import MotionCapture-Data to get it moving.
Since the CS-Biped is not made of standard-bones, I guess it won't be possible to convert and export the skeleton in a format that can be read by 3DGS.