HERE WE ARE boys! :D
Just rooted my U8650 in this damn EASY way:
download the file update.zip from here
, copy it in your SD card then turn off the phone and put it in recovery mode (volume up+on/off switch for a few seconds).
Once in the recovery menu select "update from SD , chose the file, then reboot et voilą!
Your phone is rooted!
Thank huchengtw for the chinese forum link! ;)