I’ve checked this, but it seems, that CBE doesn’t support plugins for custom field types.
I can’t find any documentation, so it would be a huge task to trace CBE and then write the code for that. If you know any developer documentation, please post a link.
For now, my suggestion is use Joomla profile for character assignments.
15MtA5fPyKWn3c7J9NSSisSNZL3Qaz7ayU
