I'm confused - if you have Comfort Access, which is basically keyless ignition, why are you putting the key in the slot? I don't even know why the slot is there on Comfort Access models - I suppose it is just a part of the BMW build configuration. The manual says that the Comfort Access key cannot be charged by inserting in the slot. Instead, there's a battery that has to be replaced periodically. Such is the case with the key for my Lexus IS250, a 2006 model.
My key stays in my pocket....