Hello,
The option to choose "Word Clock (TDIF)" is still available in Pro Tools 6.
You can choose “word clock (tdif)” in the external clock output menu in the Hardware Setup’s Main tab.
Folow the directions in Abase 7981 when transferring from Pro Tools to DA88s via TDIF.
http://answerbase.digidesign.com/detail.cfm?DID=7981
You will neeed to use a T-connecter on the DA88 and place the terminator on one end and connect the wordclock output of the 192 to the other. This is outlined in the abase above.
Hope this helps.
Mike