OpenSAML user discussion

I managed to assemble an AttributeRequest which I send using the 
SAMLSOAPBinding. The response I receive holds the requested attributes except 
for those attributes that are limited to a Requestor.

Our administrator at the university responsible for the Shibboleth Origin 
setup told me that my target implementation did not authenticate itself 
correctly. I.e. in the logs it says "Request is from an unauthenticated 
SHAR", and therefore my Target does not qualify for the attributes limited to 
the specific Requestor.

Can someone elaborate on how I'll have to configure OpenSAML to do correct 
client authentication? I already configured Tomcat with the correct 
Certificate, but this is for Server Authentication, if I am correct on this. 
Do I have to set the SSL Properties in opensaml.properties?

Thanks for any hints,
-mike