Insert row into ordered group

I'm trying to programmatically write out data to an existing LiveCycle form. In the section below named "us-doc-reference" only one blank row is showing on the form, with an ADD button.

I can write out the first row as follows:

this.xfa.resolveNode("data.us-ids.us-patent-cite.us-doc-reference[0].doc-number").value = "0793388";

How do I now insert a 2nd, and subsequent rows? From what I've read here it seems to be either InsertInstance or AddInstance, but I don't know the correct syntax.

Thank you.