There are several aspects concerning retroactivity. I am mainly referring to the fact that the minister's designation power is retroactive to 2009. That means that those who arrived in Canada on board Sun Sea, for instance, will not be able to apply for permanent residency or bring their children and husband until their five years' is up, even if they are recognized as refugees. They won't be able to apply for a passport or travel documents before the five-year period is up.
On May 1st, 2012. See this statement in context.