update specific address book record via suitescript

Hi,

I have some code im using to update an address book record.

I can see that the internal ID is available to me for the row of the address in the UI. However each time I t

// update existing addresses
var recCustomer = nlapiLoadRecord('customer', custID, null);
recCustomer.selectLineItem('addressbook', 1);   // -- this currently appears to be the only way to update a specific record in an address book
recCustomer.setCurrentLineItemValue('addressbook', 'internalid',761 );    // --- this doesnt appear to work
recCustomer.setCurrentLineItemValue('addressbook', 'defaultbilling','T');
recCustomer.setCurrentLineItemValue('addressbook', 'defaultshipping','F');
recCustomer.setCurrentLineItemValue('addressbook', 'addressee',request.getParameter('addressee') );
recCustomer.setCurrentLineItemValue('addressbook', 'addr1',request.getParameter('addr1') );