When handling user created events or creating subforms that handle the ApplyChangesBeforeCommit method, extended attributes are not saved on the User object.
Extended attributes were being saved after the User object had been created and subforms' ApplyChangesBeforeCommit methods were executed.
Beginning with Community Server 2007.1, an update to the CreateUserForm control is included that saves extended attributes to the User object before the object is saved and before subforms' ApplyChangesBeforeCommmit methods are executed.