I would charge two day rates. It's common for film composers to use two-minutes of finished music as a daily goal. John Williams is qutoed as saying something like that and I've heard it from others. The sound design would be additional days.
Congratulations on the gig!.... but good luck getting paid enough. These tend to be really low budgets from what I've seen.
Just wanted to tag this thread by linking to this forum request. I'd like to see a dedicated place on Gearslutz for dicussing production music (film, tv, and video game), the business of, and the gear used by people in this niche.