Well I've fitted mine to a BMW MKIII unit, and I have 2 minor problems.
I can set the date in the settings screen and it appears along with the time at the bottom.
However, as soon as I turn the car off and lock it and leave it, when I get back in the date has gone (time is still there and correct) and when you go into the set up screen, it's back at 01 01 00 checked the battery and it's at 3v
Struggling to get this to work. It's been suggested that using Navcoder to change the temperature display first can do it, but alas no joy.