Some more code to give you an idea on whats happening...

Breakpoint is hit in the ApplicationStarted but never goes to umbracoPage_Init.

protected override void ApplicationStarted(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
        {
            umbraco.presentation.masterpages.umbracoPage.Init += umbracoPage_Init;
        }

void umbracoPage_Init(object sender, EventArgs e)
        {
            // make sure the page is an umbracoPage; otherwise exit
            var page = sender as umbraco.presentation.masterpages.umbracoPage;
            if (page == null)
                return;

            // check that the path is allowed
            var path = page.Page.Request.Path.ToLower();
            if (!path.Contains("umbraco"))
                return;

            // attempt to find/create the ClientDependency loader for the page
            bool created;
            var loader = UmbracoClientDependencyLoader.TryCreate(page, out created);
            if (loader != null)
            {

                // set the custom path for your plugin
                loader.AddPath("DTPicker", IOHelper.ResolveUrl("~/js/bsDateTime"));

                // load the JavaScript resources
                loader.RegisterDependency(998, "datetimepicker.css", "DTPicker", ClientDependency.Core.ClientDependencyType.Css);
                loader.RegisterDependency(999, "datetimepicker.js", "DTPicker", ClientDependency.Core.ClientDependencyType.Javascript);
            }
        }

Anyone? up?

is working on a reply...