Hi Brad:
Try using the black wrinkle paint and then top coat it with the correct shade of brown.
Another option would be to take advantage of the dislike lacquers and enamels have for each other. Paint the part with a coat of brown enamel and then use the same shade of lacquer on top of it... instant wrinkles!
No, Ma, I wasn't referring to you with the line about instant wrinkles!
Mike