Kevin,
I can't remember how I did it, but you can absolutely use AC2CZ's Pacsat groundstation with the D710, as I have successfully done it with mine. I cannot remember for the life of me how I did it, however, as we only get 35deg max passes up here, and my house blocks my antenna's view to the south - so I am only able to use the highest 10 degrees of the "high" passes, and even then getting into the bird is tough.
One main thing to remember is that you have the TNC speed (9600), and you also have the serial port speed. Make sure that your serial port is making a good connection with the D710. I ended up practicing the connection on 144.39 with Direwolf (standard APRS). When i was finally able to view the packets via the serial port on Direwolf, I changed all the necessary radio settings over to 9600 packet and then the pacsat groundstation worked.
If you can't get it going, I can mess around with it this weekend and see if I can replicate my earlier success.
--Roy K3RLD