This might give some insight into what is going on in Europe with regard to emissions:
http://www.globalinsight.com/SDA/SDADetail7802.htm
At present we're on Euro 4 emission limits and certain options are not available on diesels. My wife has a 2005 E46 330 D MSport Convertible with the same engine as my 'X', but because it was made after April 2005 it had to meet the EU4 regs and no auto option is available as the auto version prevents it meeting EU4 emissions.
It has particulate filtering but the NOx limit is still breached on an auto so BMW did not make it available. The new version will be OK though.