It should be there...
PowerCLI C:\> $version
PowerCLI Version
----------------
VMware vSphere PowerCLI 6.0 Release 3 build 3205540
---------------
Component Versions
---------------
VMWare AutoDeploy PowerCLI Component 6.0 build 2358282
VMWare ImageBuilder PowerCLI Component 6.0 build 2358282
VMware vSphere PowerCLI Component 6.0 build 3205541
VMware Cloud Infrastructure Suite PowerCLI Component 6.0 build 3205541
VMware VDS PowerCLI Component 6.0 build 3205541
VMware vCloud Director PowerCLI Component 6.0 build 3191743
VMware HA PowerCLI Component 6.0 build 2591578
VMware License PowerCLI Component 6.0 build 3188616
VMware vCloud Air PowerCLI Component 6.0 build 3191743
VMware PowerCLI Component for Storage Management 6.0 build 3191741
VMware vROps PowerCLI Component 6.0 build 3191742
VMware vSphere Update Manager PowerCLI 6.1 build 3191523
PowerCLI C:\> get-command get-vdportgroup
CommandType Name Version Source
----------- ---- ------- ------
Cmdlet Get-VDPortgroup 6.0.0.0 VMware.VimAutomation.Vds
Since PowerCLI 6.0 Release 1, this command is part of a module and not a snapin. Could it be the origin of your issue?
Important: As an enhancement in PowerCLI 6.0 R1, some snap-ins have been converted to modules. You should ensure your scripts check for and add the relevant snap-ins and modules as needed.
- The following are distributed as snap-ins:
VMware.VimAutomation.Core
VMware.VimAutomation.License
VMware.ImageBuilder
VMware.DeployAutomation
The following are distributed as modules:
VMware.VimAutomation.Core
VMware.VimAutomation.Vds