How do I add director and cast to a title already existing

www.listal.com/dvd/what-happened-to-rosa

Mabel Normand is the star and isn't listed. How can I fix this? The option is not there. I can edit details, date and the like but not cast or director.

I'm afraid currently isn't not possible to edit cast or directors on dvd's

ah tis a shame but thanks for replying, I have started to notice a few that are missing the main person for some reason.