After compiling scenery mesh with SBuilder, you would shall find your newly created DEM-files in the SBuilder\Scenery folder.

With a few simple steps you finally set up your own new "Gibraltar" scenery in FS9:

  1. In your FS “AddOn Scenery” folder, create a folder “Gibraltar” with a subfolder “Scenery” and an empty subfolder “Texture”.
  2. Put your new DEM-files into the subfolder “Gibraltar\Scenery” and register the AddOn scenery in FS as usual and start FS
  3. In case you also produced textures, maybe by creating VTP polygons with SBuilder in the same go, put them inside the "Texture" folder.
  4. Start FS9 and activate your new scenery. You will then have to restart FS9 before the new settings will be working.

Enjoy your flight to Gibraltar!

If you compare the first picture – representing the result from this mesh tutorial – with the ready-made one from rhumbaflappy, you can see it would really need some tweaking make it look more realistic. 

It's especially important to avoid the holes. When tweaking your BMP heightmap, you should get rid of dark red areas and yellow spots.