the fix for sqeaky front seats plastic trim inboard backrest to seat covers? on 2007 Mercedes-Benz S550

theres a plastic clamshell type assembly that covers the inboard corner of the front seats which the seat belts bickle stem part rubs onto and any movement makes a sqeaking sound. it appears that the two part cover are not positively locked onto each other so they are slipping at their edges against each other thus making noise. i tried inserting felt. did not work. i think the fix is to glue these two together. any one has fixed this?

Asked by for the 2007 Mercedes-Benz S550