Hey Boris,
Sorry but what I wrote doesnt work... :(
New created user-fields are stored in the table _cck_store_item_users but the the Live Value function doesnt look in this table. It takes the values from joomla _users table and thats the reason why id, name,username and email work but the rest not.
I dont figured out how to save/extend the _users table. When I choose this table as storage... the field is created in _cck_store_item_users table.
But when you manually create the field in the table _users using phpmyadmin then you can map a new field in seblod to this table. And the most important thing... the Live Value Plugin works!
Maybe a DEV can have a look at it... ;)
Greetings
Skepsis