That's what I'm finding out too after testing. I expected Tmo to say that too, after all, they want to get the $20/month for the Hotspot accounts. The one thing that's causing me to think it can be done, is if the 8320 is connecting via wifi, then it's sending data (user and password) to the Tmo server. I find out what that is and try to copy it on the Mac and I may be good to go.
Time to do some packet sniffing on my network.
Update: Checking my server won't help now that I think about it. I gave the 8320 a password to access our wifi here at work. I need to know what the phone is giving Tmo at Starbucks to log into the network. I find that and I'm good. Normally one would enter their phone number and the last 4 digits of their SSN. The 8320 is preset to log in to Starbucks, so there's something in it phone that's pre-authorized. Hmmmm, what is it.