Ok, a while ago I asked this question and was told it was impossible. After tinkering around, I have found the answer! To completly remove that annoying black mask in ur in game cinimatics, just go into map options and click the "use terrain fog" check box. Next change the options like this:
Style: Exponential 1
Z Start: 0
Z End: 0
Density: 0
and ta-da! No more lame fog :D | 
