No matter how I configure the Credentials property I get a 401 exception when I try to Render the report. Here is my (latest) code:

var rs = new ReportExecutionService();
        rs.Url = "https://myserver/reportserver/reportexecution2005.asmx";

        var myCache = new System.Net.CredentialCache();
        myCache.Add(new Uri(rs.Url), "kerberos" , new System.Net.NetworkCredential("username", "password", "Domain"));

        rs.Credentials = myCache;

The URL and credentials are all correct. But still getting a 401 when I cal rs.Render(...). The Reporting Services install is sitting on a Windows Server 2008 box and requires integrated authentication.

Thanks