Inventory Transfer of serialized items

Within a Suitelet I need to create an inventory transfer for serialized items.  I am able to create simple inventory transfers for inventory items, but I've been wrestling with the detail subrecord specification without success. 

This code produces - An unexpected SuiteScript error has occurred.

var xfer = nlapiCreateRecord('inventorytransfer');
xfer.setFieldValue('location', from_location);
xfer.setFieldValue('transferlocation', to_location);

xfer.selectNewLineItem('inventory');
xfer.setCurrentLineItemValue('inventory', 'item', '10');
xfer.setCurrentLineItemValue('inventory', 'adjustqtyby', '1.0');

var detailSubRecord = xfer.createCurrentLineItemSubrecord('inventory', 'inventorydetail');
detailSubRecord.setCurrentLineItemValue('inventoryassignment', 'issueinventorynumber', '12345678');
detailSubRecord.commitLineItem('inventoryassignment');
detailSubRecord.commit();

xfer.commitLineItem('inventory');

var id = nlapiSubmitRecord(xfer);

Any assistance would be appreciated.  Thanks.