char bt = 'a';
		string b64 = "";
		if ( ch.Length> 0  )
		{
			byte bb =  Convert.ToByte(bt);
			byte[] ba = new byte[ 2 ];
			ba[ 0 ] = bb;
			b64 = Convert.ToBase64String( ba );
		}

	byte[] buf = new byte[ 4 ];

	StringWriter sw = new StringWriter();				
	sw.Write(ch);
	XmlTextWriter tw = new XmlTextWriter( sw );
	tw.WriteBase64(buf, 0 ,  4 );
				
	sw.Close();
	tw.Close();

	byte[] buffer = new byte[ 4 ];
	StringWriter sw = new  StringWriter();
	sw.Write( ch );

	XmlTextWriter xw = new XmlTextWriter( sw );
	xw.WriteBase64(buffer,  0 ,   2 );
	xw.Close();
	sw.Close();
	string b64 = Convert.ToString(buffer);