Buy apps again after mac os x reinstall?

Hi all,

i bought my macbook air year ago and I have iMovie and iPhoto installed on it. Then I also bought Pages. Few months ago I also upgrade my OS into Mavericks and all apps was there.

But today I erase my disk and install Mavericks again on clear disk. When I go to App Store it looks like a didn't buy this apps before! I'm signed in in store with my valid ID.

Do you know where could be a problem?

Thanks very much!