We probably have a bug. Would you be kind enough to create a bug report at https://issues.jboss.org/jira/browse/PLFED and attach the payload?
You can scrub any confidential details from the payload such as (ip address) etc before attaching.
Since we have very short release cycles, you will have a fix soon.
Bob, if you want a fix faster, try to fix it by cloning https://github.com/picketlink/federation
So you will end up with picketlink-core.xml and a binding jar based on ur server runtime (as5,as6,as7,tc6 etc). https://docs.jboss.org/author/display/PLINK/v2.1.1.Final
Feel free to put in a pull request with the fix.