One thing you must at least do before you can import the OBJ-file is triangulate it. The last file you made contains polygons, and this is not supported by the game and S3D.
Unfortunately I have no Wings3D so I can't help you out on that front. I'm sure someone else can help.
And Rubini can probably work out how to do the import with S3D.
[edit] Here's the update:
http://www.subsim.com/radioroom/show...71&page=30#587