If you make the entries recur it doesn't matter how far ahead they are. :-)

I noticed that my nephew's birthday was still there for November 2012, 2013 and 2014 (haven't checked later). All the other birthdays are still there as well

I wanted to make entries for a trip I'm going on in October and of course they didn't show up .

Once edited in Google calendar to make then recur in 2013 the entries popped up in the N9 calendar and they're still there (changed the interval though to 5 years to keep the calendar clean)

Not elegant but it seems to work (with PR1.3 at least)


UPDATE: the October entries survived a restart so it seems to be reliable enough