Hi Brian Jimdar,
Our official release of RadControls for Silverlight 4 is available with our official release of Q1 2010 SP1. We won't provide Silverlight 4 RTW for our Q3 2009 release. My recomendation would be to upgrade to our latest official release so you can take advantage our RadControls for Silverlight 4 RTW.
the Telerik team
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