How to stream live from two cameras?

[geteee]

Hi!
I would like to do live streaming and I have two DV cameras and I can easily stream from one of them at Ustream or Bambuser (for example), but I would like to be able to switch between two cameras. I have also tried Microsoft Expression Encoder 4, and there I can switch between the two cameras really nicely, but it can't output as RTMP which is required at least for Bambuser and Ustream. I have also tried Enosoft DV Switcher and it works fine in Graphedit, but I don't know how I would output it from there to Ustream/Bambuser/Any other similar service.

In MS Expression Encoder I can output the mixed video to the local LAN, and play it on VLC. But how do I get it streamed on Ustream/Bambuser? Or is there any other similar software which can do the switching and output as RTMP? The Adobe Flash Media encoder is not capable of this, I can change camera but there is a 1-2 sec black frame which is too much, the other two programs switch without any black between the cameras.

So, how to stream online from two cameras? I can't buy any hardware mixer at the moment because I only need this for a few days event.

[geteee]

This actually seems to be quite ok, even the free version, if someone needs: http://www.vmix.com.au/