You can do this in a modeling program: Duplicate your model, scale it a little (by normals, which is not possible in MED), invert the normals and apply a black skin. Now render both entities at the same time and position (you can scale the black model depending on object-camera distance to keep the outline at the same thickness).
"Falls das Resultat nicht einfach nur dermassen gut aussieht, sollten Sie nochmal von vorn anfangen..." - Manual
