Xbee(AT)+Arduino -----------XbeePC

[system]

Hi

I'm trying to send serial commands to arduino through Xbee
The code works fine in the arduino with usb Connection
With Xbees from arduino to PC the data is fine, but from PC to Arduino all i get is the same caracters sent backwards
Using X-CTU
sending an assemble packet this is what happen:
(red=arduino)(Blue=pc)

Alarm Sistem commandline
.>help;
.help;

Arduino code is here->
http://thirdeye.dip.jp/arduino/ProcessCommands.pde

[system]

So, it's not working and don't know how to fix it
Perhaps i should use API mode, but i need a gideline or tutorial for Xbee API mode

thanks