I'm trying to disable the Call List by adding the parameter feature.callList.enabled="0" and it even worked for a few minutes where the message center icon and the call list icon disappeared from the top left of the screen but re appeared after I added a few other parameters and restarted the phone.
To debug this issue, I did a factory reset of the phone and added just this parameter but it doesn't work anymore. Weird.
out of curiosity I did try the same and Imported a small configuration via the Web Interface. After the initial reboot the Phone no longer displayed the 2x Icons on the Top but once I went into a menu and returned to the main screen I can no longer disable this.
Factory defaulting the unit and loading the configuration does not disable this on boot up.
I would suggest you raise this as a Ticket via your Polycom Reseller so we can bring this to the attention of the Developers as you can only not disable the call list feature on the SoundPoint IP 321/331/335 .