I thought someone else had cottoned on to the ILS feature in Orbiter that disconcerts me a little, but it turns out (reading the thread) that you mean the glideslope angle and not the localizer deviation sensitivity. Still, the ILS does not really come into its own until you can set some low visibility parameters, so it is pointless to say any more about it. The pilots and flight sim users on the site will know what I am on about....
Just on the off hand, is there a way to set low visibility, by any chance?