The Mission item set in The Sims 3 is totally ridiculous. Tons of the objects do not say "Missionaire" in the name. Some say "Mission" instead of missionaire. Some have spanish-influenced names. Some don't. So finding all the items in regular play is downright impossible.
So hey, here's all the Mission items along with some Mission-like items and some walls and floors I felt went with them, all in one collection. The collection icon is that of a Spanish-ish cluster of buildings, like the ones in Pleasantview in Sims 2. :D
To install, place the file in Documents/ElectronicArts/TheSims3/Collections/User.