Creating a new item in Grid ComboBox editor template - kendo-ui

Question

I have setup a Kendo Grid with a column which contains a ComboBox editor template assigned. This works well and retrieves the items I am expecting:
columnSchema.push({ field: "Comment", title: 'Comment', editor: commentDropDownEditor, template: "#=Comment.Description#" });
Produces the following:
My issue is that I am now trying to extend the properties of the 'Comment' column so that users can enter new items i.e. comments that will, in turn, be saved to the database for reuse.
So far, I have done the following...
Setup the commentDropDownEditor function:
function commentDropDownEditor(container, options) {
$('<input name="' + options.field + '"/>')
.appendTo(container)
.kendoComboBox({
suggest: true,
change: onComboBoxChange,
autoBind: false,
optionLabel: "Select comment...",
dataTextField: "Description",
dataValueField: "ID",
dataSource: {
type: "json",
autoSync: true,
transport: {
read: "CommentsAsync_Read",
create: {
url: "CommentsAsync_Create",
dataType: "json"
}
}
}
});
$('<span class="k-invalid-msg" data-for="' + options.field + '"></span>').appendTo(container);
}
Hooked up the change event to the following function:
function onComboBoxChange(e) {
var combo = e.sender;
// check if new value is a custom one
if (!combo.dataItem()) {
// select the newly created dataItem after the data service response is received
combo.one("dataBound", function () {
combo.text(combo.text());
});
// create a new dataItem. It will be submitted automatically to the remote service (autoSync is true)
combo.dataSource.add({ Description: combo.text() });
}
}
I can see the onComboBoxChange function being hit through the Console Window (including the line where the new item is being added to the combo box datasource) but the associated Create transport function is not being executed nor is the item being added to the Combo Box.
Create function in the Controller is as follows:
[HttpPost]
public async Task<ActionResult> CommentsAsync_Create([DataSourceRequest] DataSourceRequest request, [Bind(Prefix = "models")]IEnumerable<Comment> comments)
{
if (comments.Any())
{
//await _manager.CreateCommentAsync(comments);
}
return Json(comments.ToDataSourceResult(request, ModelState));
}
Is there something I am missing/doing wrong here to get this to work?