Present additional VLAN - vSphere Standard Switch

Hello everyone.

I currently have two Exchange servers, both with NIC's that sit on the same IP range. ("abc")

I need to add secondary NIC's to each server, but the IP's need to sit on a different VLAN than the existing boxes.("xyz") (Redundancy is the goal here.)

How do I present the "new" VLAN ("xyz") to our vSphere ESXi 5.0 environment so that it's an option when adding a standard switch, instead of only "None (0)" or "All (4095)?"

Thanks for the time.

-Brandon