Finally got a reponse from support:
In vDS you can specify the VLAN trunk. Pease see the following KB regarding this:
http://kb.vmware.com/kb/1010593
There should not be any issues with having VGT and VST together so you should be ok in your environment. Please remember that connecting VST or VGT with External Switch tagging (EST) may cause issues and should not be used together, but other than that there will be no problems.
Just to be extra safe after implementing the solution, you can monitor
the network the network for proper operation.
Sergio
Sergio