Here is feedback from VideoInsight:
"We do support dual streaming by enabling the second stream in the “Advanced” Tab. We support it for most of the major brands but unfortunately none of the cameras you tested. We have recently enabled it as an option for all cameras. We defaulted 2nd stream support for all models on version 6.2.14 which is available at http://downloadvi.com/"
Thank you for the quick help.
We upgraded to the latest version and indeed I see this option of the 2nd stream now.
What I did is connect a HikVision camera to the server and enabled the 2nd stream as shown.
No I connected to the server from another PC and monitored the download on that PC.
I did not see any change from viewing the camera on a single view (where I would expect to see the main stream) and viewing the camera on a 16 or 36 division where I would expect the 2nd stream to kick in.
Really strange as I would expect this to be supported out of the box.
Anyway - thank you for your help.