changing the oil on my 206 HDI

I will be changing the oil on my 206 HDI soon I have bought the filter
and noticed a small extension piece at the bottom of the filter. Is
there a hole in the bottom of the filter housing into which this fits
or does the filter just simply drop in the housing ?

See image extension piece circled.

http://picasaweb.google.com/ianmac/DropBox?authkey=Mu4RE83dFBs#5261146585134034226

 

You will see when you remove the old filter, that piece goes upward.
TIP: Have a container underneath to catch oil, as when you unscrew the
plastic canister some oil will drop out, and also when you remove the
filter itself. I would use gloves to protect your hands from the old
oil.