Here is the promised XML response sample. I shows me having authenticate off of LDAP1 with my garnet student username of eak3992, and shows the cn being returned as my FSUID of ekromhout.

<cas:serviceResponse xmlns:cas='http://www.yale.edu/tp/cas'>
<cas:authenticationSuccess>
<cas:user>eak3992</cas:user>
<cas:fsuAuthServer>LDAP1</cas:fsuAuthServer>
<cas:fsuEduCarsUserName>ekromhout</cas:fsuEduCarsUserName>
<cas:fsuEduCarsUserName>eak3992</cas:fsuEduCarsUserName>
<cas:fsuEduUserkey>00030110516561636589</cas:fsuEduUserkey>
<cas:cn>ekromhout</cas:cn>
</cas:authenticationSuccess>
</cas:serviceResponse>

Ethan