It works because I do it.
My issue when I first tried was I didn't make a mount point to the snap mirror. Open NetApp and create a mount on the protected volume just like it was a real volume. Then assign the rights to the mount point. Then when you browse in Veeam it looks like the snapshots at the main site. The really cool part is the instant restore, mount a VM from the mirror snapshot at the DR site in Veeam, this takes only a minute and the VM is running. My DR backups use this mount now which makes remote backups real fast because they are really local.
I also found I can have Veeam make local NetApp snapshots every hour ( doing for Exchange ) then I have Veeam tell NetApp to Snap Mirror all the days snaphots at night to the DR site. This allows me to send some snap mirrors every hour for the required RPO of some VMs while others snap shot only locall all day but then sends the days worth of snap shots to the DR site off hours.
At my DR site now I have Veeam backups but no Replicas, any more. I don't need the Replicas because Veeam can mount the VM from the snap mirror very fast and you then just vmonition or run it there. My RTO is very quick now.
One other thing I found out is to be sure to use a local server for FLR. If using a snapmirror at the DR site be sure to use the ESXi server at the DR site, it defaults to one at the other side, under advance you can chose the host to recover from.
The combo of NetApp and Veeam is powerful and simple once you get it setup.