Text editors

Ok gang,

    I am trying to enhance my activity module (Teacher Plan) by adding a button (<input type="button"....) which produces a popup window.  From this window you can browse all the activities in the course and get a direct link to them.  I want to update an HTML-savvy textarea (i.e. HTMLArea) control with the link created in the popup window using Javascript.  The problem is that while I can add it when the bare HTML is visible (i.e. the control is displayed as a textarea, so I use textarea.value += html), I cannot update the HTML in the HTMLArea.  Any function call to editor.insertHTML(html) fails.  Here is a snippet:

<?php
    use_html_editor('plan');
    use_html_editor('assessment');
    use_html_editor('materials');
    print_footer($course);
?>
<script type="text/javascript" defer="defer">
<!--
    var html_match = 'plan', edit_plan],
                      ['assessment', edit_assessment],
                      ['materials', edit_materials;
                     
    function insertToTextArea(recvname, html) {
        for (var i = 0; i < html_match.length; i++) {
            if (html_match[i][0] == recvname) {
               alert("Found "+recvname);
                // Make sure that editor has focus
                html_match[i][1].focusEditor();
                html_match[i][1].insertHTML(html);  // inserts  contents
            }      
        }
    }
-->
</script>

This code is in the parent window.  When I call opener.insertToTextArea('materials', mylink) from the popup window, I get the proper alert message, but both focusEditor and insertHTML fail.

Any ideas how to do this?  I am guessing that I am not getting the proper HTMLArea pointer, thus making the function call invalid, but I do not know how to fix that problem.  Any help is appreciated.