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 (16×9 would display as 4×3 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.