RDS for AM?

I finished work on a C-QUAM (AM Stereo) transmitter, and now want to add
something similar to RDS, but not sure how to go about it. I am aware of
AMSS, but I like my wideband audio signal, and think that using the
subsonic frequencies could work.

Basically, I want to send maybe a call-sign, genre, and maybe song info.
For encoding I would porbably use UTF-16.

Any ideas?