Yes, DaCast works with Avercaster Duo. We have had broadcasters use this and the Live Gamer Portable over our service to distribute video content.
Please note, there used to be a problem with aspect ratios (16x9 would display as 4x3 with the image compacted) and DaCast over these services. This was since fixed via a firmware update to the Avercaster Duo in August of 2013. If you are still experiencing aspect ratio issues, please make sure you have upgraded to the latest firmware update.