как это примерно должно выглядеть.. если класс А : Hashtable и т.п.

using System;
using System.Collections;
using System.Xml.Serialization;

namespace Oz.Common
{
	/// <summary>
	/// HashtableTransferObject
	/// </summary>
	[XmlInclude(typeof(DictionaryEntry))]
	[SoapInclude(typeof(DictionaryEntry))]
	public class HashtableTransferObject
	{
		#region Private fields 

		private ArrayList _content;

		#endregion Private fields 


		#region Public properties 

		public ArrayList Content
		{
			get
			{
				return _content;
			}
			set
			{
				_content = value;
			}
		}

		#endregion Public properties 


		#region Constructors

		public HashtableTransferObject()
		{
			_content = new ArrayList();
		}

		#endregion Constructors


		#region Public methods 

		public static implicit operator HashtableTransferObject(Hashtable hashtable)
		{
			HashtableTransferObject transferObject = new HashtableTransferObject();

			foreach(DictionaryEntry item in hashtable)
			{
				transferObject.Content.Add(new DictionaryEntry(item.Key, item.Value) );
			}

			return transferObject;
		}

		public static implicit operator Hashtable(HashtableTransferObject transferObject)
		{
			Hashtable hashtable = new Hashtable();

			foreach(DictionaryEntry item in transferObject.Content)
			{
				hashtable.Add(item.Key, item.Value);					
			}

			return hashtable;
		}

		#endregion Public methods 
	}
}