1. Open editor.
2. Place enemy AT soldier on shoreline, location on island doesn't seem to matter.
3. Place SDV, with player as driver, 300m-400m off the coast, from the location of enemy AT soldier. Ensure enemy AT soldier is facing SDV.
4. Move towards enemy AT soldier in SDV, while at surface. Enemy At soldier should spot the SDV within 200m or so of the shoreline.
5. At about 150m-180m off the shoreline, increase SDV's depth to a minimum of 25m.
6. At this point, the AT soldier SHOULD fire upon the SDV.