The OEM radio antenna on my 99 SLK230 seems to be loose - I can wobble it a bit and am worried about water getting into the trunk area. I tried to remove the access panel which seems to be about where the inside part of the antenna mount should be but it is part of a huge panel that covers the drivers side of the trunk interior. I did discover that there is a metal brace just inside of the access panel that would prevent getting at the antenna mount. I guess that one tightens or removes the antenna from the outside of the car but have no idea how this is done. Please help. Thanks in advance.