You should check with the Fl. registration office. I really don't know anymore, since I am not working the election this year. If you have another valid picture ID, I am sure they will let you use that. While I was using public transportation, up until last year, I always used my work id (when I worked for the gov.) or my passport.
Since they are cracking down on voter fraud and all that big time this year, you might want to check to see what sorts of ID they will accept.