According to the user instructions, unregistered users can send PMs to members using uddeim when use as part of CB, but unfortunately I cannot get it to work!
I have set "enable public frontend" to "yes" in the uddeim admin "public" tab, and I have set the relevant private message tab in CB for "public" access, but I still cannot see the private message tab in the frontend unless I login to my site first. Now I'm stuck - no idea what to do.
You cannot use the profile plugin for that purpose.
When you have enabled the Public Frontend, ensure that the menu link to uddeIM is public accessable. When a visitor uses this link he will see the public frontend.
uddeIM & uddePF Development
CB Language Workgroup
CB 3rd Party Developer
Pity though that visitors have to use a generic menu item (and then of course they have to select the member they want to message) rather than simply being able to create an instant message direct from that Member's profile page (just as other Members can do).