Empty CGI variables in Windows 2008 IIS 7

I'm running CF 9 on Windows 2008 R2 Standard and IIS 7.

Most of the keys in the CGI scope are empty strings.  I've Googled for a solution but haven't found one.  I've disabled anonymous access to the web site but that prevents me from browsing it.  I've modified various IIS-specific settings to no avail.

Is it possible to get CGI.Auth_User and other values given this configuration?  Disabling anonymous access in IIS 6 allows what I need.

Thanks,

S.T.