Add a new type of Unordered List to RAD Editor

Question

I'm trying to add functionality to RAD Editor for an unordered list with a class (whatever):

<ul class="whatever">
  <li>thing</li>
</ul>

I have:

• The button showing up
• The command registered, and firing

I've decompiled RAD Editor assembly but am having trouble matching what I see in RadEditor.js with actual Javascript I'm seeing in the browser.

Update: I decompiled Telerik.Web.UI and that has the Javascript I'm seeing in my browser, but still would take any help I can get.

Update 2:
Here's what I have; get ULs before and after adding the new one, then find the new one, and add a class.

RadEditorCommandList["InsertCheckmarkList"] = function (commandName, editor, tool) {
editor.setFocus();
var elementsBefore = editor.get_document().getElementsByTagName('ul');
elementsBefore = Array.prototype.slice.call(elementsBefore);

editor.executeCommand(new Telerik.Web.UI.Editor.InsertListCommand(editor.getLocalizedString("InsertUnorderedList"), editor.get_contentWindow(), editor.get_newLineMode() == Telerik.Web.UI.EditorNewLineModes.Br, "InsertUnorderedList", "check", editor));

var elementsAfter = editor.get_document().getElementsByTagName('ul');
elementsAfter = Array.prototype.slice.call(elementsAfter);

var newElement;
for (var i = 0; i < elementsAfter.length; i++) {
    if (elementsBefore.indexOf(elementsAfter[i]) == -1) {
        newElement = elementsAfter[i];
        break;
    }
}

if (newElement) {
    newElement.className += " whatever";
}
};