Besides the well used ManagementContext vCAC also has some SOAP services for basic infrastructure communication and provisioning. With the ProvisionService, VMPS for short, you get a wrapper around some basic vCAC workflows and helper functions that abstract data manipulation of the MangementContext and others. Using this service with PowerShell is pretty straightforward with the help of the ‘New-WebServiceProxy’ Cmdlet. For short I show you how to initialise the SOAP service and list some SOAP actions you can execute. To further dive into it you can have a look at some of my other blog posts like machine import and Approval/Reject of requested machines. Here is a list of all actions (excluding all async actions):

PS > $VMPS = New-WebServiceProxy -Uri https://vcac52.sharedop.org/VMPS -Class VMPS -Namespace VMPS
PS > $VMPS;
SoapVersion                          : Default
AllowAutoRedirect                    : False
CookieContainer                      :
ClientCertificates                   : {}
EnableDecompression                  : False
UserAgent                            : Mozilla/4.0 (compatible; MSIE 6.0; MS Web Services Client Protocol 4.0.30319.18063)
Proxy                                :
UnsafeAuthenticatedConnectionSharing : False
Credentials                          :
UseDefaultCredentials                : False
ConnectionGroupName                  :
PreAuthenticate                      : False
Url                                  : https://vcac52.sharedop.org/VMPS
RequestEncoding                      :
Timeout                              : 100000
Site                                 :
Container                            :

PS > $idTkn = New-Object VMPS.IdentityToken;
PS > $idTkn.User = '{0}\{1}' -f $ENV:USERDOMAIN, $ENV:USERNAME;
PS > ((($vmps | gm -Type Method).Name
  -notmatch '^Begin' )
  -notmatch '^End')
  -notmatch 'Async$';
Abort
AcceptLeaseExtensionRequests
AcceptVirtualMachineRequest
CreateObjRef
Discover
Dispose
Equals
FireReclamationRequestEvent
FireVirtualMachineEvent
GetHashCode
GetLifetimeService
GetType
InitializeLifetimeService
NotifyGroupAdminOfLeaseExtensionRequest
RegisterExistingVirtualMachine
RejectLeaseExtensionRequests
RejectVirtualMachineRequest
RequestVirtualMachine2
SubmitReclamationRequest
SubmitVirtualMachineRequests
ToString
TriggerUpdateMachineNotesEvents
TriggerUpdateMachineOwnerEvents

When you execute actions you often have to use an IdentityToken that I always set to the username of the current user. You certainly can choose something else.