How do you get the pokenav in emerald?

Once you get to rustboro city go and beat the first gym then go north until you see the guy from petalburg woods he will ask you for a package that team aqua stole go east until you get to rusturf tunnel go in and beat the team aqua member he will give you the package and now take that to the guy who wanted it he will take you into the Devon corp and let you talk to the president he will ask you to deliver a letter you will then get the pokenav.