I feel better I'm not the only one. I ran into this exact situation as well on my 3 node failover cluster with 5 HA targets. Tried this twice. First time was before SP1 for R2. Upgraded one node, resynced, then did the second and the sync finished. During all of this the nodes started having problem...

Evaluating Starwind, latest version. HA target on two x64 Win 2008 R2 hosts. Setup the initiator on another 2008 host. Got MPIO setup. Round robin works, I can verify it by looking at network activity on both the hosts while doing large file copy. They each show half the total activity. That is perf...