TCUs prior to 09/2004 not only don't contain ANY voice commands, but they dont even include Bluetooth functionality. Its a BMW Assist function only.

From 09/2004 - 02/2005 BMW Assist + Bluetooth (No Voice)
From 03/2005 - now BMW Assist + Bluetooth (Voice commands for phone only)

My TCU was flashed by my dealer due to a fault. It was updated with new software. BMW sent out flashing kits to dealers as so many were failing. I dont know for certain, but I believe its seperate S/W and not part of the progman release disks, as like you mention I-BUS vehicles are limited on what can be flashed or coded.