I'm confused on how Raid would work with a remote SAN.
I understand that ESX uses the card on the server.
The HD's on the server are configured as a raid array. But how do you configure the SAN as an array?
With a SAN you'll have some sort of management application or interface. That's where you'll configure RAID arrays and assign LUNs to hosts. The host accessing the SAN won't see the underlying array, but rather just the LUNs that you assign to the host.
In a SAN (and also a NAS) the RAID is implemented on storage side.
You do not see at all from hypervisor level... you just see some kind of "virtual disks" (called LUN in SAN's terminology)