lainyrache on "Meta keywords on zenpage pages"

Hi
Can anyone please tell me how to add meta keywords on my zenpage pages?
On my albums and images, I can add tags which appear in the meta keywords tag.
But I can't figure out how to do it on pages. I have the html_meta_tags plugin installed, but my keywords tag is appearing empty <meta name="keywords" content="" />
because I don't know how to populate it.

Thanks for any help!