I take Latin in my school, and have known a few people to actually take the Latin SAT II. Usually people who have done well in at least a year of Latin poetry (i.e. prose or Virgil) have had the background to score well.
What year of Latin are you in? Are you usually getting awarded after each NLE (National Latin Exam)?
I think, as with the AP Latin exam, they do expect you to be able to translate on the spot.