Open Visual Studio with the WCF service and run it. Copy the url it is running in. Then open another instance of Visual Studio with your silverlight project and run that but use the url for the development server running your WCF. You can set a breakpoint in the WCF service and in the silverlight project both. When your call happens, you should be able to hit the breakpoint in the WCF service and trace what is happening in the save.

Another idea is to set your project up to use local data via the configuration change like the sample does. Then when you have issues like these, you can just point to local data and trace it easier. This is how I typically do it, but setting a breakpoint in the service works well also.
Timothy

>The entity is null after calling GetAllEntities but this code works:
>

>public Stores()
>        {
>            InitializeComponent();
>
>            this.Title = ApplicationStrings.StorePageTitle;
>            this.StoreController.GetAllEntities(delegate(object s, EventArgs e)
>            {
>               this.StoreController.Entity = this.StoreController.EntityList.FirstOrDefault();
>                this.DataContext = this.StoreController.Entity;
>            });
>        }
>

>Now that I have that working I tought I'd try saving the entity. It does not update the table. I trace all the code and it sees the modified entity but the viewing the WCF calls with Fiddler shows no update is being called. No errors either. I can't step into this:
>function:public virtual void SaveEntityAsync(EntityType entity, EventHandler callBack, object userState)
>...
> --> SubmitOperation submitOp = this.TempDomainContext.SubmitChanges(OnSaveEntityCompleted, userState);
>so I don't know how to troubleshoot. Any advise on how to find the problem will be appeciated.
>Thanks