Hi! I had the same problem. The oil filter cover in black plastic needs a special tood that you'll be able to find in a BMW dealership for approx. 10$. It's a silver metal tool that you put on the filter and you'll be able to unscrew the filter housing.
Without this tool, your only solution is to try with your hands, what I wasn't able to do...
I'll try to post a pic of the tool at home later tonight.