Yeah, I should have been more complete in my post. In customer_details.tpl, use something like this. I used the variable company for the 2nd address line, but if you did something else, change this code accordingly:
Code:
{$userinfo.b_firstname}{$userinfo.b_lastname}
{$userinfo.b_address}
{if $userinfo.company ne ""}
{$userinfo.company}
{/if}
{$userinfo.b_city}, {$userinfo.b_state} {$userinfo.b_zipcode}