Hi Cosy,
with the configuration you have we can adapt any of the following DMZ configurations which are supported in vSphere infrastructure. This is based on the standard switches.
Partially Collapsed DMZ with Separate Physical Trust Zones
Partially Collapsed DMZ with Virtual Separation of Trust Zones
Fully Collapsed DMZ
Ref : http://www.vmware.com/files/pdf/dmz_virtualization_vmware_infra_wp.pdf
we can have advance DMZ features with the help of vDS like Nexus 1000v.
Please refer http://www.vmware.com/files/pdf/dmz-vsphere-nexus-wp.pdf