Tshark Vendor specific dictionary field

Hi,

I'm trying to call an attribute from a vendor specific dictionary included for the following included radius dictionary "dictionary.rfc4679"

How can I call attributes specified in this dictionary as a field in Tshark?

e.g. I want to call the listed attribute

ATTRIBUTE       ADSL-Agent-Circuit-Id                   1       string

As a field in the following command:

tshark -i eth1 -T fields -e radius.Event_Timestamp  -e "ADSL-Agent-Circuit-Id"

Thanks.