Get-SwisObject not providing all object types for groups

[thefreakquency]

The following command to obtain Members of a Group: Get-SwisObject $swis -Uri 'swis://HOSTNAME/Orion/Orion.Groups/ContainerID=13/Members' returns:

Get-SwisObject : Invalid key properties specified for entity Orion.ContainerMembers.
Parameter name: filter
At line:1 char:1
+ Get-SwisObject $swis -Uri 'swis://HOSTNAME/O ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [Get-SwisObject], FaultException`1
    + FullyQualifiedErrorId : SwisError,SwisPowerShell.GetSwisObject

Similar errors for the following objects:

• ContainerStatus
• MemberSnapshots
• OrionSite
• StatusCalculators
• WorldMapPoint

Only the following works:

• CustomProperties
• WebUri