I have installed User-Submitted Posts Plugin.
I have rigged that up to send the user info, instead of to custom fields, to create a guest-author.
I have successfully created such a guest author and am now stuck on how to add a user to a post.
I want to do this behind the scenes. I have the post id, and the guest author Id and display name, and email.
How can I do this? Something along this line...
wp_set_post_terms($PostID, $NewGuestAuthorID, 'author', true);