Autogen loading radius

Hi. I have spent some time searching the AVSIM forums before posting this: there must be a thread somewhere covering this, but I haven't found it.Is there some way of increasing the radius at which autogen scenery loads? The problem I am seeing is most evident when flying at night, but must occur all the time I assume: autogen buildings suddenly appear from nowhere, and I don't mean several kilometres out, but what seems to be almost at the last minute, pretty much under the aircraft's nose, so to speak. Buildings then disappear again just as soon once you fly over them. At night the effect is very odd indeed - looks like a series of catastrophic power-cuts.My PC is pretty high-end and frame rates are good - I get this effect even with frame rates of 40 or more. I have tinkered with fs9.cfg display settings (which subject must run a short second only to pornography in the amount of web space devoted to it!!), but can't seem to improve things, and wonder if I am missing something. I tried different display settings - MIP mapping, draw distances, different autogen densities etc. but haven't found anything helpful so far. I've run out of ideas.Help much appreciated. My current Display config in the fs9.cfg file is below. Thanks.Martin[DISPLAY]UPPER_FRAMERATE_LIMIT=30TEXTURE_BANDWIDTH_MULT=400[TERRAIN]TERRAIN_ERROR_FACTOR=95.000000TERRAIN_MIN_DEM_AREA=10.000000TERRAIN_MAX_DEM_AREA=100.000000TERRAIN_MAX_VERTEX_LEVEL=21TERRAIN_TEXTURE_SIZE_EXP=8TERRAIN_AUTOGEN_DENSITY=5TERRAIN_USE_GRADIENT_MAP=1TERRAIN_EXTENDED_TEXTURES=1TERRAIN_DEFAULT_RADIUS=9.900000TERRAIN_EXTENDED_RADIUS=4.900000TERRAIN_EXTENDED_LEVELS=1307992