Create Amazon CloudFront Distribution use Custom Origin. Require AWS SDK for .NET http://aws.amazon.com/sdkfornet/

CreateCFDistributionWithCustomOrigin.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Amazon.CloudFront;
using Amazon.CloudFront.Model;
using System.Collections.Specialized;
using System.Configuration;

// Require AWS SDK for .NET http://aws.amazon.com/sdkfornet/

namespace AWS_Test
{
    class Program
    {
        static string accessKeyID = "Your AccessKey ID ";
        static string secretAccessKeyID = "Your Secret AccessKey ID ";
        static AmazonCloudFront cfClient = null;

        static void Main(string[] args)
        {

            using (cfClient = Amazon.AWSClientFactory.CreateAmazonCloudFrontClient(accessKeyID, secretAccessKeyID))
            {

                Console.WriteLine("Create CloudFront custom distribution");
                CreateCFDistributionWithCustomOrigin();

                Console.WriteLine("Finish");
            }

            Console.WriteLine("Press any key to continue...");
            Console.Read();
        }

        static void CreateCFDistributionWithCustomOrigin()
        {
            try
            {
                CreateDistributionRequest req = new CreateDistributionRequest();

                CloudFrontDistributionConfig config = new CloudFrontDistributionConfig();

                CustomOrigin customOrigin = new CustomOrigin();
                customOrigin.DNSName = "www.your.site.com";
                customOrigin.ProtocolPolicy = OriginProtocolPolicy.HttpOnly;

                config.CustomOrigin = customOrigin;
                config.Comment = "Test Custom Origine Distribution";
                config.Enabled = true;

                req.DistributionConfig = config;

                var response = cfClient.CreateDistribution(req);

                String xml = response.XML;

                Console.WriteLine(xml);
            }
            catch (AmazonCloudFrontException cfEx)
            {
                Console.WriteLine("An Error, number {0}, occurred when create cloud distribution with the message '{1}", cfEx.ErrorCode, cfEx.Message);
            }
            catch (Exception ex)
            {
                Console.WriteLine("UnknownError:{0}", ex.Message);
            }
        }

    }
}