Please help with reskinning

I am reskinning alien3's artic tanker to be the trailer that the truck in the movie Duel pulls. It has Texaco labels on the sides, a walkway on top and doors on the sides. I am unable to change there from white to the colour I want. Could someone tell me what texture files I need to change to get the white parts the desired colour.

I have permission from alien3 to upload the truck and trailer, so if you are thinking "What is in this for me?", I can tell you that you should have the Duel truck to use after I colour the white parts.

Thanks for your help.

Don't worry, as you can see in my signature, I have finished it and am allowed to upload it. Can you please delete this thread moderators.