Hi -
You can download the Remove Subscriber Properties tool from here - http://www.ciscounitytools.com/Applications/Unity/RemoveSubscriberPropertiesFromAD/RemoveSubscriberPropertiesFromAD.html
This is the safest and easiest way to remove the CiscoEcsbu* attributes from the user account. If you are familiar with Active Directory and comfortable using ADSIEdit, you can also edit the user and clear each of the attributes beginning with CiscoEcsbu*. But the tool link I've provided does that all for you from the Unity server. It is supported with Unity and Exchange - see the online help. Installing on the Unity server is also safe and does not impact users on the server, meaning no reboot or service restart.
Hope this helps! Sincerely, Ginger