Morning ajones1722,
Yes it is very possible to stream your video over the Internet, most of it would be down to the configuration of your firewall/router. You would also have to make sure the gateway information is correct on your dreambox so it can route the packets correctly.
However, I think you'll find you don't have nearly enough bandwidth to achieve this. I believe that cable modems have a maximum transmit speed or 128kbps, even if your on ADSL the upperlimit will be 256kbps. The big selling point of broadband is the download speed.
For the amount of information your dreambox transmits to view live streams via the web interface would be somewhere in the region on 8Mbps. I am guessing to what the actual bandwidth would be but I wouldn't imagine I am far off.
It was a good idea though, I thought of trying something similar myself once.
Trooperboy