Does someone how to deal with the parameter "ReferenceName" ?

Hi guys,

Recently our team is trying to create Azure VM through the methods provided in Azure.Management.Library. To be more clear, we tried to create a VM along with a chef client with it, hope that this extension(ChefClient) would do something automatically once the VM had been created. To achieve that we have to pass a ResourceExtensionReference instance to tell VMAgent(meybe,not much sure) that an extension should be installed after VM is ready. Now one thing bothered us quite a lot was that there's a REQUIRED parameter of ResourceExtensionReference called "ReferenceName", but nobody knows what kind of value should use for that parameter. Below is the portion of the code:

ResourceExtensionReference ResourceExtensionReference = new ResourceExtensionReference()
                {
                    Name = "Chef",
                    Publisher = "Chef Software, Inc.",
                    ReferenceName = "Chef", // This the perisher!
                    State = "Enable",
                    Version = "11.10.4",
                    ResourceExtensionParameterValues = new List<ResourceExtensionParameterValue>
                    {
                        new ResourceExtensionParameterValue{Key="Client.rb",Type="Public",Value=rbStr},
                        new ResourceExtensionParameterValue{Key="Validation key (.pem)",Type="Private",Value=pemstringStr},

                    }

                };

At first we thought there maybe some instruction we could found in the internet, but after 5 hours searching we gave up that because there're quite few articles related. Then we tried, tried, tried, failed them all of course :(

So, can someone kindly tell me:

1.what value should we use to set this parameter?

2.Where can we get this value?

3.Why we need that value since the same thing is much more easier through the Azure Management Portal page(I mean create a virtual machine along with a chef client)?

Any idea will be appreciated!