Sean, your "gotcha" is that settings made on the local web page interface (e.g. 192.168.x.x) are overwritten by the settings stored in the OBiTALK portal. On the IP phone, it's amusing or annoying, depending on one's mood, to watch this happen, just as you described...it accepts your change, then the portal sees that something's different, so it pushes another change and reboots the phone.
So: make the change in Expert Mode on your OBiTALK portal account for the 1062. If you haven't already figured it out, you must first un-check both boxes to the right of the parameter to be changed, before you can customize it. Click the submit button to save and push the change.
You can disable OBiTALK programming entirely, but I suggest working from the portal for now.