In the latest software update there is a checkbox in the SmartView control panel that will allow you to set widescreen view. It was only recently released, so you might have bought your Smartview Duo might not have had the setting at the time.
You can download that from our main website by clicking on the support tab and selecting your product.
We've also gotten similar requests for the ATEM lineup, but have not had a chance to add that feature yet, but I believe it is something we'd really like to do.