code: public static void decodeFieldData(BaseField field, String string)
      {
          if ((string == null) || (string.length() == 0))
              return;
          byte[] ba = Base64.decode(string.toCharArray());
          InputStream is = new ByteArrayInputStream(ba);
          DataInputStream daIn = new DataInputStream(is);
          field.read(daIn, false);
      }
docs: Change this base64 string to raw data and set the value in this field.
  WARNING - This requires 64bit encoding found in javax.mail!
  @param field The field containing the binary data to decode.
  @param The string to decode using base64.