Well, the modified driver/inf file did actually work. I found out the problem was with the dialer and the latest Sprint connection manager. For some reason, both programs did not see the modem.

All I did to make this work was to create a new dial up connection on Vista after the phone was connected on usb mode. I set the phone number to #777 and no username or password.

Thanks for your help on the driver though. I could have not done it without that step.