Solution:
make use of sendToNoficationChain() method to notify Depot assistant once the ajax call is complete.
The Depot assistant via the considerForNotification() method will then call modelChanged() method to update the scene
***************************************************
WBDepot.prototype.loadDepotContents = function(result){
if(result === null){
Mojo.Log.warn(“Retrieved empty or null contents from the depot, using defaults”);
this.loadDefaultContents();
}
else
{
Mojo.Log.info(“Retrieved contents from the depot”);
this.contents = result;
}
//Notify the chain that depot has completed retrieving contents
Mojo.Controller.getAppController().sendToNotificationChain({
type: “depot”
});
}

**********************************************************
/**
* Since depot transactions are asynchronous we need
* to set up an observer to listen to notifications of successful
* completion of ajax call
* update our model
*/
DepotAssistant.prototype.considerForNotification = function(params)
{
if(params && params.type == ‘depot’)
{
this.listModel.items = this.model.getListContents();
this.controller.modelChanged(this.listModel);
}
}

I promise that I will not forget about Part 5 and I will get to it just as soon as I can.

Thanks for the feedback!

It was really a good tutorial. Waiting for SQLite version tutorial.