how to show bill-to adress in cart only when filled out?

[websister]

Hello everybody,

(I modify this post a littele bit, because I was not clear about what I want to do: have to spezified my thoughts a little bit ... )

I don't want to show both adresses above the cart table if the user didn't fill out his adress (so no matter if he's guest or not).

How can I manage this? I think I have to find out if there is date in the fields of BTadress ... but it doesn't work ...
I already tried to create this request (but it seems to be not empty, no matter if logged in or not):

<?php if(empty($this->cart->BTaddress['fields'])){
         echo "don't show" ;
      } else{
         echo "show" ;}?>

?? How can I find out if customer is not logged in??

Thanks for any help ...

*.tina