Just had a chat with HTC support who have let me know that the Firmware enabling Internet Connection Sharing on the HTC Mozart is being blocked by Orange in the UK. Here's a cut+paste from the chat, the query was "Will the Firmware update enabling Internet Connection Sharing on the HTC Mozart be made available to Orange UK users?"
Him: Hi XXXXX, thank you for contacting HTC Support, I am looking in to your query now.
Him: OK. At the moment we cannot confirm as this needs to be confirmed by Orange due to a business conflit. Be aware that Orange also sells Broadband services and as we seen with Andorid devices the Tethering options has been removed.
Me: So Orange are purposefully blocking the feature?