Case sensitivity for untokenized fields

Hi, I have a address model.

I make the city and the state field untokenized. It looks like Ferret
doesn’t perform downcasing for these fields in the index.

so the search can’t be done case-insensitively.

how do I solve this problem?

Downcase the indexed terms as well as the search value?

Is there a simpler solution?

Thanks.
Yaxm