[xwiki-users] How to change user ownership of documents ?

Hi all, Here is my problem, I switch from xwiki DB authentication to our corporate LDAP, and some user will have their login changed. Ex: in xwiki they created some basic username such as their first name, and in LDAP they will have to enter their corporate login that is usually the first letter of their first name concatened to the seven first character to their name. Some users in this case have already created a lot of documents and if I change directly the Xwiki.userName in the database this does not work as it seems that the login is used to reference all document from a specific user. So how to change the ownership of document from old name to new name ? Fabien