Changing key bindings?

Having played the beta and now the release for a little while, one thing I wanted to do was change the key for rotate map. I highly dislike using the middle mouse button and would much prefer to hold down a key press. There's no 'controls' option in the game menu (but I don't really expect to find one in a TBS). After looking through the game folders (both Program Files and My Documents) I haven't found any obviously labeled places to change my key setup. Does anyone know if it is possible to do this and how? I know rotate isn't really necessary in this sort of game but it can help around the mountains and to see the pretty graphics.