I would be very interested to know how u end up Marko.
I have the same problem with my gtr, I attempted using a small spot of WD40 then rincing with soapy water and rubbing over with a polish (washed the wd40 off quite quickly).
Appeared to work quite well, however i can see this being quite time consuming. Besides its quite difficult to get a cloth to some of the panels that are quite dirty in mine.
Also dont like the idea of spraying WD40 all over my paintwork.