Add Transaction - Items can't be referenced by name?

I am building a PO import tool that parses a spreadsheet and imports it into a Netsuite Purchase Order via webservices due to cumbersome PO entry UI in Netsuite.

I'd like to be able to do the following:

[INDENT]PurchaseOrder nsPO = new PurchaseOrder();

// Set up vendor, location, initialize item array, etc...
// ...

RecordRef rrItem = new RecordRef();
rrItem.name= "Unique SKU of Item";

WriteResponse wr = service.add(nsPO);[/INDENT]

When I run this code, I get this error:  "Please choose an item to add".  When I instead add the item using its internalId, I do not get this error message, the PO is created in Netsuite, and the crowd goes wild.