Hi there VYSSUTE and welcome to the forums
I am not too sure about whether you can Tech2 the HCE to re-program it from Single Zone to Dual Zone.
(Holden Dealers apparently cannot carry out a colour head unit conversion, but I do not know what their limitation is).
I know that they can replace a faulty headunit or fascia (So setting the VIN number, and seed keys for the headunit and fascia)...
Soooo I am assuming that they should also be able to re-program the HCE module ?????
I am also assuming that for Holden, the most difficult part is adding the additional wiring for the sensors.
As for the required sensors and the resistor mod....
Another member here MartinM was the member that came up with the resistor mod for the HCE, after discovering that his SS did not have the required sensors (Outside ambient, Cabin temp, and the sunload sensors)....
To clarify, there are two types of sunload sensors, the first is just for the automatic headlights (Daylight Sensor). (Typically fitted to Omega, SV6, and SS models).
The second type also has the above sensor, and an additional drivers side and passenger side sunload sensors, which are solely used by the DZ climate control system. These are a different type to the daylight sensor in that they provide different resistance values to the headlight sensor.
The sunload sensor looks exactly the same, regardless of the model, however the DZ climate control models have 6 pins instead of the usual 2 (or 4, cant remember) pins on the connector....
For the interior ambient temperature, I dont know if Holden snuck them in on later models, but the quickest and easiest way to tell if its fitted is to pull the lower trim off on the drivers side, and check for a 1.5 to 2cm hose that connects behind the trim piece near the little vent hole on the trim piece.
The quickest way to tell if you have an outside ambient temperature sensor fitted, is to see if your HVAC system can tell you the real outside temperature. (A standard feature on both Ford and Holden Climate Control systems going wayyyy back to Ford EA Falcons and VN Series II Commodores)
If the temperature reading is exactly the same, all the time (Give or take 1 degree), then the sensor is not present, and has a resistor fitted to trick the HCE in to thinking it is...
To be honest though, Holden have been very stingy with fitting stuff that isnt required on the VE models, so I really doubt that the required sensors will have been fitted at the factory, or even Holden fitting the required wiring for the sensors.
Finally, one good thing about the HCE module is that if you have any difficulty programming the thing, you can always try and source one from a wrecker. (It doesnt require VIN matching or anything like that)...
Hope this all helps ....
Cheers