Just in case some newcomers are stuck on this one. With Iclone's ability to have supersized sets now Mist and Fog kind of don't behave at the moment but will, I think, Later.

This is a simple fix and can be as versatile or as multi-layered as you wish.

This is the actual landscape I'm using. Simple camera usage means we don't ever see this but it comes across as a feasible environment because of the edge mountains made of oversized garden rocks which have wonderful definition and editable to boot.
I forget who made these Rocks Hi Def. But congratulations to you because they work perfectly for what I wanted them for when I asked.

(Anbove...)  "Just thought I'd open me a Public House for the sake of it. " ;):P

(Above.)  Here there are about 3 planes each at about 10% opacity each but set afar at the end of the street. I feel it cuts the edge off contrasts and keeps things looking "comfortably unobtrusive" as when things are hazeless the colours and contrasts of everything from 0 to 100 infinity are way too loud.

In IClone 5.x we don't get any shadow glitching using multi-planes for Mist and Haze. Here we see 16 planes
at about 95% transparency setting each and placed equidistant to each other.

See these supersized HERE and HERE.

Armstrong.