I'm pleased to announced that we just pushed a preview of the SLS publishing plugin for Expression Encoder 2 live:
http://download.microsoft.com/download/2/2/a/22a8da23-ffa7-4e5a-8fed-8239d3a7b322/SLSPlugin for Expression Encoder 2.msi
This plugin makes it very easy to publish and manage your encoded Silverlight video experiences online via the Silverlight Streaming service from within the Expression Encoder application.
As well as adding support for Expression Encoder 2, the plugin has a number of enhancements:
Hope this helps,