ok.. its working now.... the magic packet are being created by xbmc python....
import socket
s=socket.socketsocket.af_inet, socket.sock_dgram
s.setsockoptsocket.sol_socket, socket.so_broadcast, 1
s.sendtoxff6x00x50x2cx01x99x5216, "255.255.255.255",9
searching on internet, ive founded that i need to declare the sockets options before sending a packet to a broadcast address. now its working just copy the script and change the mac address 00 50 2c 01 99 52 with the one of your network board.
you will need to be sure that your computer supports wake-on-lan. to have sure of this, view your network board features and your motherboard bios.