UILabel sizing during device rotation

In my app I have two labels. Second one should be positioned below the first one (with some small const padding). The first label is multi-lined and takes all possible width. So after changing interface orientation, its real height can change (because necessary line n开发者_运维技巧umber can change). That's why autoresizing mask can't help me here.

So.. How can I control this and display labels correctly even during interface orientation change animation?

Damn. I'm so sorry about this question. I've really googled before asking and tried to read docs. But somehow I've missed this and this with great details about my question.