Scenic Byways Signs and MUTCD

Aloha everyone, I have what I hope is a very simple question. The Hawaii Scenic Byways Program is wanting to develop a state byway sign (including logo) and would like it to be multi-colored. I have seen other multi-colored scenic byway signs in other states, however, the MUTCD does not have guidelines for multi-colors. How do I get around that? Better yet, how did you get around the MUTCD color guidelines. Since the scenic byways program is very unique, there must be something that I cannot find. Any help will be very appreciated......and might even get you a coconut.

Mahalo,

Dave Zevenbergen
Hawaii Scenic Byways Coordinator