Undefined setBufferTime

[AndreiRO]

When trying to set buffer time on a client that i want to play a live stream
from FMS3, i get undefined error:

1061: Call to a possibly undefined method setBufferTime through a reference
with static type flash.net:NetStream.

Piece of the code that generates it:

[Q]
var nc:NetConnection = new NetConnection();

var ns:NetStream;
var btn:but=new but();
var btn2:but2=new but2();


function playStream(){
ns = new NetStream(nc);
ns.setBufferTime(2);
ns.addEventListener(NetStatusEvent.NET_STATUS, eventListener);
ns.client = new CustomClient();
video.attachNetStream(ns);
ns.play("clientPlayStream");
}
[/Q]

nc.connect("my_streaming_url"); is called when the client starts.