Buy the game extra - on the product page click on "this is a gift" (or words like that) button, later you give the email addy of the gift recipient. I gifted my new commander with a repaint pack using my "special day" discount to pay for it, worked a treat, no issues at all.
(Although currently my separate recent free sidewinder paint in that account doesn't show up - support says there is an issue with some repaints not showing in game and that a fix is due in the next update.)
EDIT:
P.S. After today's patch, the free repaint was available in-game.