Address Subrecord - populating prior to page loading

This new address subrecord in 2014.2 is throwing me for a loop.  Prior to 2014.2, we had some simple code in the before load of an Item Fulfillment to pull in an address from a custom record:

nlapiSetFieldText("<span style="text-decoration:underline">shipcountry</span>", site_info.getFieldText("custrecord_site_country"));

Now in 2014.2, this no longer works and it appears that I need to update the shippingaddress subrecord instead.  I have attempted to do this in my before load of the Item Fulfillment but get the following error (based on https://netsuite.custhelp.com/app/answers/detail/a_id/39551/kw/shippingaddress):

// 2014.2 Code - try 2  <span style="text-decoration:underline">var</span> shippingSubrecord = nlapiEditSubrecord('<span style="text-decoration:underline">shippingaddress</span>');  shippingSubrecord.setFieldValue('country', 'US');  shippingSubrecord.commit();