ssoLogin w/ samlAssertion from idp fails: Signature is not trusted or invalid error

I am attempting to login via the java sdk ssoLogin() with a samlassertion from an openam idp.  The result is a signature validation exception.  I must be missing some trust configuration, but where?

The assertion looks like the here:https://communities.vmware.com/servlet/JiveServlet/download/2276630-112203/saml-assertion.txt

And the test connection here: https://communities.vmware.com/servlet/JiveServlet/download/2276630-112204/ssologin.txt

The stacktrace is attached.

I found the source of AbstractProfileBase.  The verifySignature method uses a SignatureTrustEngine to verify the signature.

Another related question.  Other postings in this forum w/ questions related to java sdk ssoLogin reference a ssoLogin example in the sdk.  I have not been able to track this example down in any of the downloads.  Can someone point me to where that example lives?

thank you.