Modify A Table In A Parent Window Froma Child

I'm having problems changing a table from a child window.

What works (but I really want to add more complex objects to teh cells
not just plain text)

var myTable = self.opener.document.getElementById("MY_TABLE");

var row = myTable.insertRow();
var cell = row.insertCell();
cell.innerText = "New value";

I've tried the two below methods but they both fail.

var myTable = self.opener.document.getElementById("MY_TABLE");
var row = myTable.insertRow();
var cell = row.insertCell();
cell.appendChild(self.opener.document.createTextNo de("New Value")); <--
Gives me an error of "Invalid arguement"

I've also tried

cell.appendChild(document.createTextNode("New Value")); <-- Gives an
error of "No such interface supported"

Any ideas?