Not an answer to your question, but be careful, DSS v6 failover cluster has issues with Hyper-V failover cluster yet (BSOD of VMs when doing iSCSI failover on DSS). At the moment you must put your VMs to saved state before you can failover on DSS. I hope open-e is working on that problem ...

BTW: We use also Areca controller which works well with DSS.