Retain Aperture metadata in photo upload

I would like to retain the image metadata I created in Aperture when I upload to WordPress. In particular, I would like not to have to retype the alt text and caption for all of the images in the WordPress library (of which there are many!). I have figured out that Aperture’s “headline” maps to WordPress’s “Title”, and that Aperture’s “Caption” becomes WordPress’s “Description”.

If anyone has any thoughts on how to solve this issue, it would be much appreciated.

Thanks!