Have to add some info: the antenna rod must be exactly the inner dimension to slip over the circular connector to press the catch hooks together to make it possible to push the connector out of the plug.
Here is a pic of the connectors where you can see the hooks, don't know how to explain that in English that good, but you can see the hooks
http://www.realoem.com/bmw/showparts...96&hg=61&fg=15