Google Cloud Print from a specific tray

I am trying to implement silent printing from a .NET web application using Google Cloud Print, the requirement is to print different documents from a different tray such as invoices from Tray 1, envelopes from Tray 2, business cards from Tray 3.

Below is the code I am trying to follow:

postString.Params.Add(new PostDataParam { Name = "vendor_ticket_item", Value = "{\"vendor_ticket_item\":[{\"id\":\"psk:JobInputBin\",\"value\":\"ns0000:Tray 2\"}]}", Type = PostDataParamType.Field });
p.Params.Add(new PostDataParam { Name = "title", Value = title, Type = PostDataParamType.Field });

      

        
        
        
      

    

It doesn't work, I even tried various options in https://www.google.com/cloudprint/simulate.html -> Submit Job API and nobody seems to get documents printed from a specific tray.

Please suggest anyone to reach Google Cloud Print from a specific tray from any type of code