Hoge.cs

using System;

namespace EnumName.enums
{
    public static class Hoge
    {
        public enum Value
        {
            Aaa,
            Bbb
        }
        public static String GetName(this Value v)
        {
            //TODO get from attribute.
            return v.ToString();
        }
    }
}

Program.cs

using System;

namespace EnumName
{
    using enums;
    using Hoge = enums.Hoge.Value;

    class Program
    {
        static void Main(string[] args)
        {
            Hoge h = Hoge.Aaa;
            Console.WriteLine(h.GetName());
        }
    }
}