there are 3 solution(well 3 and a half):
1 gummi pfledge from bmw(the 1 and 1/2 is buy another siliocne spray, cheaper...)
2 German solution: print out the following picture and tell your dealer to do what german dealer did to "krizZz"(member of german forum zroadster.com....not polite to link another forum....but we are all z drivers...)
then "energy" from the same forum went to dealer and put felt under this part of the roof....look at this thread:
http://www.zroadster.com/forum/bmw_z...ml#post1365169
3 the italian solution, with quite good pictures.....:
http://www.bmwpassion.com/forum/show...=164174&page=5
I hope this helps, anyway I use a strong dose of silicone spray on a little cotton towel, then I apply it to the roof seals , whan partially opened(and it's better also when you have to clean up the rear glass of the hardtop) every time I wash the car.....just a precaution , but no rattles or whatever in 15 months.
Francesco