Yeah, I saw that. However, I don't like to do any retrofit in other style than the original. For instance, the 'electronic box' (plastic box in which the telephone module is located) is much larger than the new, bluetooth module. There is a special foam to fill the gap - its P/N is 4E0 035 733 C, and I paid for it less than $25 at the dealership.

Now, about that pinout... I have a better conversion (which should be more suitable for those who have the cradle with SIM card reader as it has more wires)... but use this information at your own risk!:

If you want to know the reason why I came up with a better conversion you may continue to read, otherwise you can stop here.
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The old conversion is not wrong, but this one seems better to me. I wanted to leave unconnected as few wires as possible.
First, the new unit has +12V on pin 1 and -12V (GND) on pin 2. So pin 2 will be the main ground. The old, 42-pin connector had pin 37 as main ground (as you can see in the attached pictures) and the other two brown wires are for additional ground (for various sub-systems). Of course, it's the same ground, but the main ground has a thicker wire for heavier load. This doesn't matter anymore because in manufacturer's specifications, the +12V wire is as thin as the others (you can connect both +12V wires from the old connector for a heavier load, but that's not really necessary because in the original schematics there is only one thin wire for +12V on the new unit), but still, pin 37 was the main ground on the old connector and it's logical to connect it to the main ground on the new connector.

Pins 8 and 29 from the old connector are not present in other conversions that you may find on the internet, but if your car has them, then you may find above the proper corresponding pins on the new connector.

Pins 15 and 16 are ground pins. There are many ground pins on the new connector, but pins 32 and 33 are the best match, as I needed two consecutive pins whose positions were just right for the length of the two wires. This makes these two wires to be the only wires assigned to row #2 of the connector. If you want to have a single-row connector, then you have to find other ground pins for that.

Pins 7 and 28 from the old connector are the only ones who will be left unconnected, because they are related to the SIM card which, on the new unit, is not located in the cradle anymore (it resides in the phone instead).