WP Event Manager – logo is gone

By mistake I have deleted “Logo” on the Field editor page and now I can′t add the field again. Or I can add a field and call it “Logo” but I think the metakey is wrong (and can′t be changed) and this means, that when I try to upload a logo, is doesn′t appear on the single event page.

How can I add the Logo field right again?

The page I need help with: [log in to see the link]