VCAC 6.1 REST API - AWS EC2 - values for subnet and security groups seem to be internal

All,

Came across this while provisioning EC2 from VCAC 6.1 REST API - I launched firebug after making a request to a VPC-backed instance (think t2.micro instances that have to be behind VPC)

      {        "key": "provider-__amazon.subnetId",        "value": {          "type": "string",          "value": "8"        }      },      {        "key": "provider-__amazon.securityGroups",        "value": {          "type": "string",          "value": "24,32"        }      }

Those values don't make sense to me in either a vCAC or AWS perspective. Perhaps these values are local to vCAC? Indexes in arrays?

The reason I'm suspicious of this is when I look at how the "Provision Into" field is generated:

{        "key": "provider-Cafe.Shim.VirtualMachine.ProvisionInto",        "value": {          "type": "string",          "value": "2"        }      }

I realized that "2" is the zero-index of the array being used to populate the dropdown for provisioning location (see attached vcac-index.png).

I guess my question here is - what referencing value do I use to assign EC2 subnets and security groups?