giving a bump here, hehe
Hello, i've been trying this as well, i don't know if you had any progress with this, but i must tell you, i did this succesfuly with objects in SA, and with everything in VC, the problem with peds in SA, is that, when you export the mesh, to, say OBJ. you lose the rigging, with any format, you will lose the rigging of your mesh, so let's say you model a ped in Blender, export it to .3ds, and import that model from 3D studio, you gonna have to rig it all again from within 3d studio, that really sucks, but the greatest issue with SA an Blender, is the skeletons.
Now, how did i edit sa objects in blender?
well, first, you must have gmax or 3dstudio, at least, then you import your object dff into 3d sutdio(or gmax for that matter) export your file to .3ds, import your .3ds in blender, editi however you like, export it again to the same .3ds.
Back in 3d studio, using the same scene as when you imported your dff, simply import you modified 3ds, delete the screwed up bones that Blender left, and selecting the original mesh, then your modified modified mesh using Ctrl, join them into one, now edit you joined mesh, and delete the vertices that used to be your old mesh.
Export it this way, and it should work, for me at least it worked, any doubts, just ask here.