OK, it's very tricky to get that piece out the first time.
First of all there are two screws that screw it to the air vent above, you need to remove those.
*edit* you've found those I see.
there are now two screws to each side of it.
If you look at the pics of one taken out you will get an idea maybe.
http://www.en4cer.co.uk/Tutorial.htm
these are some photos which will be the base of a tutorial I am putting together.
You should notice the extra pieces down the sides which have the screw holes. You will need a small stubby philips head screw driver.
It will probably be best to remove the OBC and the sunglass holder so you can reach up and behind.
Also have some plasters/bandaid ready coz you are more than likely going to scuff your fingers/back of hand.
The lilliput in their at the moment is one I got from CarTFT.com it has the new 10 pin plug. The older one is now in the headrest, that came from hong kong. Although the cases have been swapped.
No probs.