I tried everything to repair my leather/tex panels, over time and with allot of heat, the material shrinks, so even heating it up and glueing it back in place, it still pulls away. I tried vinal top glue, 3M super 33/77 and several others. I finally just gave up and bought new panels. Cost is not too bad, about $160 from the dealer for the leather/mb tex panels for late model 190's with the speakers in the door.
One thing to remember, if you do purchase new panels and you have power seats, MB no longer ships the panels with these holes pre-cut, you have to cut them yourself. Kind of scary, one slip and there goes your new panel.
I have pics of this install on my web site if you want to check it out.