I have always streamed my DM600 to my PC, and now that I have the VU+ Duo, the streaming is silky smooth.
I never have used the "Web TV" button on the web interface. I simply bring up the interface in my browser.
192.168.0.1 is the IP of my box.
Select the current active bouquet, and the current channel shows with a link for EPG and stream.
Click on the stream link, and open the .m3u with VLC and off it goes
I should add that depending on your tuner/transponder setup, you can change and view other channels on the TV while streaming the original channel to you PC.
It is also possible to record the stream on the PC with the VLC record button.