rtmpdump not playing ustream live video

[monkeylittle]

I'm trying to get the video in this ustream test page to work:

http://www.ustream.tv/channel/Test-Page

I'm now able to successfully connect but there is not data streaming from the server back. I compared wireshark captured packets with the Flasher Player that is working and with rtmpdump and find with the Flash Player, the sequence is connect() followed by playing, like this (IP masked):

6087 76.657003000 x.x.x.x 199.66.239.125 RTMP 2267 Handshake C2|connect('ustream')

6111 76.898062000 x.x.x.x 199.66.239.125 RTMP 105 playing()

Withe rtmpdump, the sequence is connect() followed by createStream() then FCSubscribe():

Invoking createStream
DEBUG: Invoking FCSubscribe

I tried both with and without --live option and it results are the same.

So how do I make rtmpdump issue an AMF3 command playing() like what the Flash Player is doing?

Thanks for your help.