ADFS integration with SiteMinder, Event ID 147

I am trying to integrate a client with SiteMinder into my ADFS, but ADFS is throwing Event ID 147 when it receives the token.

http://technet.microsoft.com/en-us/library/ff641740(v=WS.10).aspx

The client assures me that the token is in fact signed with the certificate they have provided me, and I can verify that it the cert they provided is configured on theCertificates tab of the claims provider trust properties.   How can I capture the token data received on my end so I can verify this?  I am an ADFS newbie!  Thanks.