The transaction password is only needed if you are using the 3D Secure Service.
All of the settings under the Enable 3D Secure checkbox pertain to the 3D Secure Service.
The only settings needed for authorize.net are the transaction key and login.
All other settings on that page are under the enable 3D Secure checkbox, so are provided by the 3D secure service and are not needed if the enable 3D secure checkbox is not checked.