Embedded resource reference not working

I'm trying to move an image and a style sheet from a user control to embedded resources in the assembly. I have used Reflector to see that the image and .css file are embedded in the assembly, but when I try to access them using the URL created by ClientScript.GetWebResourceUrl(), the resource is not found. I'm stumped.
Assembly default namespace:
TestWebApp The paths to the files (marked as BuildAction: Embedded Resource) are
TestWebApp/Resources/CSS/PaymentHistory.css TestWebApp/Resources/Images/loading.gif And so my resources are registered as:
[assembly: WebResource("TestWebApp.Resources.CSS.PaymentHistory.css", "text/css", PerformSubstitution = true)] [assembly: WebResource("TestWebApp.Resources.Images.loading.gif", "image/gif")] User Control (in the same assembly) that accesses the resources :
TestWebApp.UserContr ...