[DonC]

DMV clerks are like counter clerks at auto parts stores. They aren't necessarily knowledgeable about all the regs that apply to a non standard application.
Get a copy of the appropriate regs (SB 5585), read it so you're familiar with the applicable parts (highlight if necessary) and take it with you the next time you go to the DMV. Should help sort out any confusion.
If worse comes to worse check with different DMV offices until you find one with someone who can read and comprehend English. Not a crack about anyone in specific but I've been in more than one situation where people just don't comprehend what's written.
DonC