you have/had starmark and it seems mb did a retrofit as well as a product change mid-cycle.it sounds as if starmark does not cover the retrofit yet they would have redone your mirror if it was under regular warranty period.i'll tell you what i would do:
now i'm pretty sure that the mirror would be replaced under starmark warranty and so i'd be looking to 'make it fail'befor the warranty runs out.these mirrors are famous for failure and so it would be beleivable.it's crazy but it may be your only recourse-other than paying in full