To be honest Cyberek, i've hoped for a little more help than "gk_custom.js" as i'm sure it's not that difficult for you to explain and wouldn't take you more than 10-20 seconds. But if that's all i can expect, anyway, i've learned sth today...
Thanks Pawel for the help, but i wanted to implement the original efffect. Maybe someone else finds a way to port them - i still hope for more.