Vraciu: I took a look at the skin you submitted.
Some how you are completely missing the concept of lighting (spec,env,power) maps.
It appears you simply grey scaled your diffuse map. This will not work very well.
As an example the star emblem on the wings should pretty much be all the same value in the spec and power map.(note different values between the spec and power, but in each map they should be consistent across the emblem) What those maps are doing is controlling how shiny /dull something is. You need to think in terms of paint , i.e. is it flat/glossy/semi gloss excreta and how each would reflect light differently . And not in terms of colors or brightness of the diffuse map.
HiTech