Why not have gig ethernet switch from the ESX boxes ? 100mb is way too slow...also best practice is to have two switches as if the one fails youre whole enviroment will go down!
I just read their document, I think the starwind required Windows 2003 or 2008 installed on SAN that need to buy
microsoft lic and starwind lic, right?
Yes, you need W2K8 (preferred) and Starwind HA license.
Obviously you need two SAN-boxes for Starwind HA with number/type of HDs and RAIDx to your needs.
For HA sync between the SAN-boxes you need an extra 1Gb connection. Two for redundancy.