Just noticed this after some more digging. It appears (in 1.0, at least), you can only edit the sublist if you have the reference to it, via adding it to the form in a Suitelet. nlobjSubList SUITESCRIPT 1.0 The content in this help topic pertains to SuiteScript 1.0. If you are interested in the latest APIs, check out SuiteScript 2.0. Primary object used to encapsulate a NetSuite sublist. This object is read-only except for instances created via the UI Object API using Suitelets or beforeLoad user event scripts. To add a sublist, you must first create a custom form using nlapiCreateForm(title, hideNavbar), which returns an nlobjForm object. After the form object is instantiated, you can add a new sublist to the form using the nlobjForm.addSubList(name, type, label, tab) method, which returns a reference to nlobSublist.