iControlREST LTM Virtual Server - Source Address Translation

Hi Folks

I'm just trying to setup some simple virtual servers using IControlREST and the powershell invoke-restmethod command.

I've managed to get most of it working except for defining properties that contain an array object as the value.

The property I'm having problems with at the moment is the SourceAddressTranslation property of a virtual server.

Using a powershell array and the convertto-json command the JSON body that I am sending is:

{
    "destination":  "1.1.1.1:0",
    "translatePort":  "disabled",
    "sourceAddressTranslation":  {
                                     "type":  "automap"
                                 },
    "name":  "VS_name",
    "ipProtocol":  "tcp"
}

Is this the correct format? When I invoke the REST put everything else is created without a problem and no errors are returned however the sourceAddressTranslation field is empty

Any ideas on what I'm doing wrong?