DataMapper: In-table Foreign Key with non-standard name

[eluser]Genki1[/eluser]
Follow-up question:

Now that my $has_one array includes customized attributes for a relationship, how do I specify other relationships that are to be used with DataMapper's default settings?

In other words, would I specify the 'user' relationship like this...

Code:

// related models that each record in this table can have just one of.
var $has_one = array(
  'user',  
  'lookup' => array(
   'join_other_as' => 'account_type') //ITFK is account_type_id, not lookup_id
);

...or like this?

Code:

// related models that each record in this table can have just one of.
var $has_one = array(
  'user' => array(),  
  'lookup' => array(
   'join_other_as' => 'account_type') //ITFK is account_type_id, not lookup_id
);