puh, pretty complex, that formats, materials etc.

What is Specular Color/Power (FSDS) used for?
Which is the best quality format to save a texture in if I want to include an alpha channel?

best,
rev

Sorry, I didn't see this post  ,
but however, I use FSDesignStudio for 3D Modelling and applying the textures and materials to the 3D data.
FSDS is payware (abacuspub.com - somewhere on that site ), but it has a freeware pendant called GMAX (in a subfolder of your FS2004 cdrom1 I think - Not sure how about GMAX on FSX disc).
For texturing I mainly use DXTbmp for opening and saving into that special DXT formatted bmp.
The textures itself I make them with either Paint.Net (freeware, just google) or Photoshop (payware).

If that doesn't answer your question - I am not sure if I misunderstood you - what are fresnel maps?

I can't belive no one wants to answer my questions!!!!!!!!! 
I also can't belive there are only people who don't know it at SimV!