As of September 2017, Veeam does not support a native S3 interface for use when connecting to Wasabi. In addition, Wasabi does not support a direct interface to Veeam Cloud Connect due to the absence of a Veeam native S3 interface. Veeam has indicated the native S3 capability is coming in Veeam 10.x (see https://www.veeam.com/blog/leverage-vtl-on-amazon-aws-object-storage-s3-glacier.html). Veeam customers should contact their Veeam representative for more info on this. Wasabi is a member of Veeam's partner program and will certify this new Veeam capability once it's available.
Another approach to using Veeam with Wasabi leverages an approach developed by another Wasabi tech alliance partner, CloudBerry Labs (see https://www.cloudberrylab.com/blog/how-to-store-veeam-backups-in-cloud-with-cloudberry-backup/). This approach has been successfully used by several Wasabi customers.