I've clicked on "customize user_table_name" below the user list in the admin panel and I've realized, that I can't enter/change a regexp for the following "system" fields: Username, Password, Email, Name, Status, ReceiveMail, Newsletter. In our system, we'd like to have some regexps for those fields. I'm quite sure I can add these regexps to the appropriate def file (the one from the user_table) in the def folder.
Question to the GT developpers: wouldn't it be possible to unlock these fields so that one could enter regexps via admin panel?
Any answer/comment is highly appreciated.