losing dates in iphoto export

[kevindosi]

i'm trying to leave iphoto in favor of picasa so that i can organize photos in folders and have easy access to them from the finder. i used an application to copy all of my photos into folders based on their events and it worked like a charm. turns out, though, that there are quite a few photos that have no exif data in iphoto but, somehow, iphoto still has the correct date set on them. when i copy them, though, the date is lost. does anyone know how i can export my entire library or copy all photos and retain those dates?