That is a shame. I am in the process of evaluating CB and need that kind of functionality desperately for a site I have to build. Do you have any suggestions how to work around this (current) limitation?
You can use JACL to get some basic functionality into Joomla but then you would have to make alot of code changes on your own in the CB system to do what you want.
Sorry - I can't. Alot means just that the changes have to be carefully planned at two levels. The ACL framework which is more or less missing from the current versions of Joomla and Mambo (not sure about 4.5.3) and that once these changes are made the right hooks and validations have to be implemented in CB.