[Terryk]

you can have a look at the attached article (it's a service information bulletin directly from bmw in 2006) I just found from my search in a colleague club. the only negative is the price of that material...I wonder if one could get it cheaper outside bmw cause the prices I found are extremely ridiculous

ps: it is mentioned that you should avoid applying carbaflo


EDIT:
I finally decided to go with the bmw's service information bulletin way, so I bought an anti-friction tape and I applied it on the upper surrounding roof panel (as mentioned in the sib). NO more creaking noises. i couldn't be more happy...finally!