[Plugin: Co-Authors Plus] subscribers as co-authors

I’m not getting the subscribers-as-coauthors thing to work with WordPress 3.2.1 and Co-Authors Plus 2.5.3.

I set the coauthors_plus_allow_subscribers_as_authors option to 1 (using the mysql shell, because I didn’t see a place to do it in the admin?), but even so, when I try to use the autocompleter thingamabob it doesn’t let me use subscribers.

Any thoughts?

http://wordpress.org/extend/plugins/co-authors-plus/