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Easiest solution is to find a new visor complete from a junk yard if possible. Opening that up might not be difficult but closing it may require some upholster skills or sewing techniques. But I think they made from some like plastic foam or something so as mentioned above, rather get another one.
Vanity mirror in 2004 CLK55 should come out with the plastic mirror enclosure if it's like the E-class (looks same to me). There are four retention points and if you pull in the right area the mirror enclosure is easy to remove. The mirror is held in place with simple plastic retainer clips that are part of the enclosure. You should be able to change without any problem. Pictures appear the same. No upholstery skills needed.