I can't stand to be defeated by a graphics problem. I have a reputation to maintain.
Well, for whatever reason, the game had a problem with the shades of purple you used - so I fiddled with the shades until I got something that looked purple in the game. I don't think it looks all that great, but as you see in the screen shot, it's fairly close to what you intended, and it is purple.
The attached .pcx has the added advantage of adding the faction colors for SMAX, which won't affect use in SMAC. Enjoy.