You need to keep with KV with the original row, so you need to use the row key from the result:

    KeyValue kv = result.get(0);
    result.add(new KeyValue(kv.getBuffer(), kv.getRowOffset(), kv.getRowLength(),
         QueryConstants.ARRAY_VALUE_FAMILY_BYTES, 0, QueryConstants.ARRAY_VALUE_FAMILY_BYTES.length,
         QueryConstants.ARRAY_VALUE_NAME_BYTES, 0, QueryConstants.ARRAY_VALUE_NAME_BYTES.length));