Powerview Cannot connect to the server due to a security issue. The server may not have been able to match the host for silverlight

Hello,

I have a sharepoint 2010 sp1 CU Dec 2011 server with a SQL Server 2012 SP1 CU4 reporting services instance.  I am able to open Power View and use it normally when bypassing the ISA Reverse Proxy server.  However when going thru ISA I receive the following Error.

Power View  Cannot connect to the server due to a security issue.  The server may not have been able to match the host for Silverlight.  This error appears after I click yes on an Internet Explorer Display Mixed Mode prompt.

I've seen a couple references to this issue but not much.  This one mentions a clientaccesspolicy.xml file but I haven't had any luck with that.  http://connect.microsoft.com/SQLServer/feedback/details/716433/cannot-connect-to-the-server-due-to-a-security-issue-the-server-may-not-have-been-able-to-match-the-host-for-silverlight

Any Ideas?  Thanks.

Ryan