Also remember, the player will recognize the intro [In], the verse [V] and the [A] chorus as Latin (all must be used with a double-bar). So you can "trick" the player, depending on how you avoid the B, C or D. This is useful in those occasional odd tunes like Linus and Lucy where there's only a brief swing section.
[edit] You can put a [C] or [D] anywhere you need to, but if you don't include a double-bar, the player will ignore it and continue playing Latin.