I missunderstood you
I thought you were using 3dstudio max for your modeling program.
I'm sure that the .3ds export from any modeling software should be relatively close to the same......there should be an [export animation] option in the export menu when you go to export.
The spacewarp modifier is used for any single mesh that you want to animate externally by use of a skelatal animation library as opposed to animating each individual character one by one.
You can create a single animation skeleton and then use that skeleton as the base for all your character animations by using the same skeleton in it's base pose and then merging each character's physical mesh into the skeleton one at a time and then using the spacewarp modifier to attach the vertices near each animation bone to that bone.
It's a pretty time consuming method but in the long run it will save you tons of animation time.
If you are using character meshes that are made up of several objects you will not need to use the spacewarp modifier but the drawback is a less life like character.
sorry if i havent helped....i havent really used any other modeling software but gmax.
3D modeler for C&C Source
www.cnc-source.com