CL500 Stereo Question

Theres a blown speaker in my '00 CL500 - and is driving me nutz. I took off the door panels today and the door speakers & tweeters are just fine. The distorted sound was coming from the center of the dash. Upon further inspection, I found out that there is a speaker just above the A/C vents in the middle of the dash behind the plastic grill.
My question is - How do I remove the plastic grill to get to the speaker?? Please help me out - because that little speaker is ruining my music-listening experience.

Thanks,
Jesse

So, nobody knows how to remove the A/C vents??