I managed to get speed camera data on my Nav - following advice from Mathmos here:
http://www.bmwnavaddpoi.co.uk/
It wasn't easy to create the eng.lsc file, but once you have it it's easy to copy the disc insert the new file and burn a copy with the poi data installed.
If you have any doubts that we are plagued by speed cameras check out these screen shots
If anyone would like any help with this I would be happy to oblige. I can also upload the files needed so that all you have to do copy the disc, insert the files and burn.