Making car-skin for this game

[knuckle327]

Hello, new to here and was wondering if any experienced skin creator has tips on how to properly make the alpha (.bmp) for a skin. I followed the flatten then greyscale tutorial, but found that it often ends up making bright color really reflective.

I'm not too sure if posting here is the right place, but I saw some mentioning about this game's engine being older than one's like Maniaplanet, which makes making alpha channel quite difficult.

(I also found a tutorial about this in the Tutorial forum, but the images are gone....)

thanks