[mellojoe]

I know this is late, and it may or may not still be relevant. However, have you tried this?

touch the power key, it brings up a QuickList of functions.
Select WIRELESS MANAGER.

Highlight the PHONE and hit select. This will turn the phone functions OFF. You can also enable or disable Wi-Fi and/or Bluetooth from this menu.

I don't know if this will still allow data, but I believe it will. It should only turn off the calling features.