Questions regarding _mco textures

[KKB 0]

Quote from this thread:

If you are far enough from ground to not to see detailed textures and not far enough to see only the satellite texture (sounds silly I know ), you will se some gibberish over the content of satellite image based on the position of detailed surfaces. The gibberish is MCO texture, which is meant to add ground detail on middle range. It is multiplied (like in Photoshop) over the satellite texture.

This is image for Combat Photo thread illustrating the appearance of MCO textures (see black dunes and generic sand textures multiplied over monotonous satellite texture):

http://img240.imageshack.us/img240/2770/mi244vn6.jpg

After reading this I'm pretty sure I understood the concept, what's missing is a way to create _mco textures.

I'm also puzzled by the description of the _mco type in the BIKI:

Quote[/b] ]multiply color map, texture used to multiply with color map (as cdt) without fade out filter, average color should be 0.5 in all R G B channels

How do I get this 0.5 average? I can see the current average in the histogram, but I have no clue how to change it.

Anyone here who can shed some light on this?