In reference to my previous post about the new invocation method introduced on April 10th, after due consideration with the Silverlight runtime team, we decided to pull out this feature.

It allowed you to distribute an application hosted in Silverlight Streaming as a Windows desktop application which allowed you to make abstraction of the web site hosting, but it didn't have the same behavior on all browsers and required Internet Explorer to be installed on your machine. This is against the Silverlight cross-browser paradigm to which we want to remain true.

We'll be working on addressing the same use case (desktop invocation of a cloud-hosted Silverlight application) in a cross-browser implementation.