You'll have to add a vendor dictionary to freeradius's dictionary files /usr/share/freeradius/ (if I recall correctly) and make sure the vendor dictionary is configured to load in the /usr/share/freeradius/dictionary file using $INCLUDE dictionary.vendorxyz and restart freeradius.
I used the ldap mapping /etc/freeradius/ldap.attr to map my vendor attributes to the ldap attribute which I chose. It helps to run freeradius in debug mode to troubleshoot. You run debug mode using the following freeradius -X. The catch is this is debian and there is a bug so you actually have to run this command instead LD_PRELOAD=/usr/lib/libperl.so.5.10 freeradius -X.
Here some info about the bug
http://www.packetfence.org/bugs/view.ph ... &history=1Hopefully that helps you. I spent quite a bit of time figuring it out and still have lots to learn.