Custom Sublist - Adding Line Items

I created a support case for this (719129), but I thought I would ask here as well...

I have a "Before Load Function" deployed for a Sales Order that adds a sublist to the shipping tab:

var sublist = form.addSubList('custpage_shipping_quotes', 'staticlist', 'Shipping Quotes', 'shipping');
sublist.addButton('custpage_shipping_get_quotes', 'Get Quotes', "msGetShippingQuotes();");
sublist.addField('custpage_col_ship_type', 'text', 'Ship Type');
sublist.addField('custpage_col_price', 'currency', 'Price');

In my client side script "msGetShippingQuotes", I want to add lines to my custom sublist. I tried using this:

nlapiSelectNewLineItem('custpage_shipping_quotes');
nlapiSetCurrentLineItemValue('custpage_shipping_quotes', 'custpage_col_ship_type', shipType);