I think you first should make the cable and then bug everyone here about the flash. The program to flash your phone is either Victor or PST, flashes take from spunlock site or www.remzone.ru
, first install pst 6,0 then victor, then connect the phone point to pst directory for the drivers. Reboot turn on the phone read info, download language pack you need flash the phone. In perfect situation you should not flash 720 into 720i and lower version than you have got in your phone.