Adding values to an existing custom property

Hi, I'm new to SolarWinds and I am hoping that someone can help me with a problem that I am having and cannot find an answer to.

I have an existing custom property drop down control populated with values and I would like to add additional values via the Rest Api.  I am making the following call:

https://<Myserver>:<MyPort>/SolarWinds/InformationService/v3/Json/Create/Orion.CustomPropertyValues

and passing the following JSON payload:

{

    "Table": "NodesCustomProperties",

    "Field": "CarrierName",

    "Value": "aaaTest"

}

Making this call via PostMan returns the following

{

    "Message": "Entity Orion.CustomPropertyValues does not contain any key properties.\r\nParameter name: entityType",

    "ExceptionType": "System.ArgumentException",

    "FullException": "System.ArgumentException: Entity Orion.CustomPropertyValues does not contain any key properties.\r\nParameter name: entityType\r\n   at SolarWinds.InformationService.Core.CrudProcessor.<CreateInternal>d__18.MoveNext()\r\n   at System.Linq.Enumerable.First[TSource](IEnumerable`1 source)\r\n   at SolarWinds.InformationService.Core.CrudProcessor.Create(String entityType, IDictionary`2 properties, IQueryExecutionContext context)\r\n   at SolarWinds.InformationService.Core.InformationService.Create(String entityType, IDictionary`2 properties)"

}

If anyone can point me in the right direction, I would appreciate it.