Change oil filter on citroen c4 1.6 diesel?

would like to know how to remove & refit the oil filter on my 1600cc C4 the filter is a type I have never used before it it is not the old type metal canister screw on type. The filter housing appears to be made of plastic and the new filter I have is a new paper type filter that fits inside the plastic housing. the housing doesn't appear to have any clips holding it on and I am unsure how to remove it so I can change it.

There are no clips.

But there is a large hex head moulded into the top of the rubber covered cap. Unscrew the whole body by turning the hex nut with a socket.

The paper filter then just pulls out of the cap that you removed.

http://citroenc3owners.com/Citroen-c3-tools/topic8.html