Thanks a lot!
Seems I made a blunder: The 3D model I tried to import was simply low poly!! Dang!
The preview looked very detailed.
SU imports 3ds files ok - apart from the fact that they are often "exploded", meaning all the different parts are not where they are supposed to...?
Strange.
Now I´ll check to see if I can export the hi-poly files from SU to .eps files.