Have you added the VLAN to the trunk port on the physical switch? without that being set the physical switch will drop any packets it has received with that VLAN ID leaving the ESX host. Further the Physical network will not know where to send any packets that are created for that VM from within the physical environment.
can you create another machine on the same VLAN (on the same host) and try connectivity between those two machine on the same host, if that is sucessful vmotion the machine to another host and try the same test.
this will tell you if your vDS is configured correctly within the environment and your problem is external to your virtual environment