I have downloaded the same version and planning to do some testing next week :)
I seem to remember in case of virtual appliance you need to configure a Linux Backup Repository in Veeam and use that one as a target. The Veeam VDMS component is only included in fw 188.8.131.52 or higher.
I wrote an article some time ago with regards to creating a Linux Repo for Veeam:
In your case:
1. Create a share in DXi
2. Follow the second part of the article and put the DXi hostname and point to the share created in first step.
Hope this helps. BTW Depending on work I might be able to do some testing next week :)
I have a running Veeam-Repo over CIFS running...but not directly a Linux-Repo.
There is DXi6900 (VTL, $88'000) which have FW 3.X only ?!