I found CCSettings in My Documents/CarrierCommand (not the doc by the same name in the main CC folder). I opened this file with notepad and found/replaced all instances of "padup" (without quotes) with "w". I did the same with paddown, replacing it with "s", padleft, replacing it with "a", padright, replacing it with "d". You could probably use any letter on your keyboard, but I chose these, knowing that I wouldn't be using them.
In the game options, I was now able to successfully replace the up-down-left-right keys with my arrow keys. Up and Down properly showed the arrow keys, but for some strange reason, left and right were designated as "left mouse button" and "right mouse button." However, in game the vehicles correctly identified all four arrow keys for movement as well as the left and right mouse buttons for the various UI actions and weapon firing. So it worked fine.