[xwiki-users] Users can't log anymore

Hi, Since a few day, my users are not able to log anymore into the xwiki platform, I suspect that my tests with LDAP may have some thing to do with it. Thanks to my luck, I am still able to log in with the admin right, and I tried to reset all users passwords so that they can login again. But this seems not working at all throught the Xwiki administration page, why ? I am currently trying to erase the password directly into the data base but the data model for user is not very trivial. I have found that users are managed as XWikiDoc and I still need to find how the String contenaining the password is linked to which user, I had also a look to the xwiki datamodel page but it is tagged as obsolete ! Could anyone helps me ? Thanks in advance, Fabien